C, Si: +4

Ge: +4 (+2 unstable)

Sn: +4, +2

Pb: +2 (+4 unstable)

Oxidation number: +4 —> +2 (inert pair effect)

Strength of covalent bonding (M-X)

- no unpaired e = strength decreases 

- has unpaired e = strength increases(C->Si), strength decreases(Sn->Pb)

Catenation 

- decreases down the group

- C good overlapping p(pi)-p(pi) orbitals

- Si poor overlapping p(pi)-p(pi) orbitals (larger size than C)

Chemical properties (reactivity increases down the group)

- O2 —> oxides

- S —> sulphide

- Halide

- Acid (cold, no reaction), (hot has reaction)

- Alkali —> [MO3]2- & H2 (except C)

- Metal 

    - C —> carbide

    - Si —> silicides

    - Ge, Sn, Pb —> alloy

Carbon

Allotropy

1. Diamond

2. Graphite

3. Fullerene

Oxides

1. Carbon monoxide, CO

2. Carbon dioxide, CO2

Carbonate

1. Carbonate - CO32-

2. Hydrogen carbonate/ bicarbonate - HCO3

Carbide

1. Ionic carbide (saline carbide)

2. Covalent carbide (metalloid carbide)

3. Laterstitial carbide (metallic carbide)

Halide (CX4)

1. CF4 - gas

2. CCl4 & CBr4 - liquid

3. CI4 - solid

Silicon

Allotropy

1. Sand

2. Flint

3. Quartz

4. Agate

Oxides

1. Silicon dioxide / silica (SiO2)

2. Silicate (SiO4)4-

3. Aluminosilicate 

Type of glass

- Soft glass

- Hard glass

- Flint glass

- Jena glass

- Pyrex/Corning glass

- Crooke’s glass

- Quartz glass

- Ground glass

- Reinforced glass

Silicones

1. Disilicone

2. Chain silicone

3. Branched silicone

Halides (SiX4) - unstable (except SiF4)

Hydrides (silanes) - form catenation

Tin

Allotropy

1. Alpha-Sn (grey)

2. Beta-Sn (white)

3. Gama-Sn

Oxides

1. SnO2 (+4)

2. SnO (+2)

Halides (SnX2 is more stable than SnX4)

1. SnCl4

2. SnCl2

Sulfide

1. SnS

2. SnS2

Lead

Oxide

1. PbO

2. PbO2

3. Pb3O4

Halide [Pb(II) is more stable than Pb(IV)]

1. PbX4

2. PbX2

QUESTION :
What beaker(component) should we use to handle HF acid? 

-Normal oxidation num is +4. 
-Down the group, oxidation num +2 becomes more stable due to inert pair effect

-Si -> Pb tend to form ionic bonding

-Catenation- C showing the greatest tendency to form stable hydrocarbon & Si less stable to catenation due to larger size of Si

-C allotrape (diamond, graphite (use as lubricant and act as oxidizing agent), fullerene (“bucky ball”) – truncated icosahedrons

-Oxide (ligand) - CO (toxic gas) & CO2

-Halides- does not undergo hydrolysis (C has no "d" orbital)

-Carbides- (ionic, covalent & interstitial)

-Oxides – silica, silicate & aluminosilicate (zeolite)

-Silicate glass (sand + metal silicate, aluminosilicate, borosilicate)

-Silicones – Si-O-Si-O bonds in chains (disilicone), rings & branches

   -uses as lubricants, in cosmetics,              breast implant shell and etc

-Halides- all halides exist as SiX4- undergo hydrolysis in water except SiF4

-SnO2 -> roasting -> pure tin ore(SnO2) 

-Sn -> electrolysis -> SnO2(anode) &     Sn(cathode)

-Sn allotrape (alpha-Sn, beta-Sn & gamma-Sn)

-Tin-plague (change from beta-Sn to alpha-Sn)

-Oxide (amphoteric oxide)

   -SnO2 (white tin) does not dissolve in   HCl, HNO3 & aqua regia 

   -SnO (black tin) more base than SnO2

-Halides (SnX2 is more stable than SnX4) - SnC2 – strong reducing agent

-Sulfide - exist as mono (SnS- can easily oxidize to SnS2) & disulphide (SnS2)
Lead (Pb) 

-Pb (mineral-galena, PbS)

-Oxide (amphoteric oxide) (exists as PbO(yellow) , PbO2(brownish or black) & Pb3O4(red))

-Halides (PbX4- PbF4 & PbCl4 exist) (PbX2- all halides exist) –

  -Pb(II) halide is more stable than Pb(IV) halide 

 

- valence electron, nsnp

- oxidation number of +4

- down the group, +2 is more stable due to inert pair effect

 

Inert Pair Effect

- describes the preferences of late p-block elements to form ions

 whose oxidation state is 2 less than the group valency

- inert pair effect means non-participating of the outer most ns² electrons

in chemical bonding

- occurs when electron are pulled closer to nucleus, making them more stable 

 And difficult to ionize

- down the group, stability +4 decrease, +2 increase

 

Catenation

- the ability of electron to be bonded to one another to form long chain

- the tendency decreases down the group

- carbon - have greatest tendency due to good overlapping p(pi)-p(pi) bond

- silicon - less stabled due to poor p(pi)-p(pi) bond overlapping because the 

        Large size of Si

 

Reactivity

- increases down the group

 

CARBON

- exists in air, igneous rock, anthracite, bituminous rock, ignite

Allotropy

- diamond, graphite, fullerene, lonsdaleite, amorphous carbon

 

Diamond 

- can be synthesized from graphite

                 P=125kbar

         Graphite ---------> diamond

                 Catalyst , Rh/Ni , T =1500-2000k  

Structure

- carbon bonded together by covalent bond

- high mp (4000 c)

- carbon bonded to other 4 carbon atoms having sp3 hybrid

 The valence e are used up, no free electron, does not conduct electricity

 

Graphite

- prepared by Archeson process (high temp. Electrical furnace)

Structure

- made up of stacked of two dimensional carbon sheets

- bonded covalently to 3 other carbon (sp2 hybrid)

Properties

- soft

- conduct electricity, have free electron

- pencils and lubricants

- oxidizing/ reducing agents to form intercalation compounds

 

Fullerene

- consist of big carbon framework consisting even nuimber of carbon

         C_{32 ,} C₄₄, C_50, C₆₀, C₇₀ 

 

 

Structure C₆₀

- truncated icosahedrons

- C₆₀ is essentially a section of graphite curled up 

- has sp2 containing 30 c=c bonds and retains the delocalized

 Nature of graphite

 

COMPOUNDS OF CARBON

 

Oxides

- exist as CO2 and CO

 

CO

Preparation

- dehydration of formic acid by conc. H2SO4

- reduction of CO2 by hot-red C

Properties

- colourless gas, no smell

- burned with blue flame

- toxic gas, strongly bonded with hemoglobin than O2

- strong reducing agent

- act as ligand in the formation of carbonyl complexes

   - CO donates a pair of e to transition metal to form coordinated

Covalent bonding

Uses

- production of pure Ni metal using Mond process

- synthesis gas in steam reforming process

- Hydroformylation (produce higher alcohol)

 

CO2

- linear molecules, non-polar, sp hybrid

Preparation

- reaction of acid with calcium carbonate

- heating of calcium carbonate

Properties

- colourless gas

- solid CO2=dry ice

- dissolve in water ---> carbonic acid

- react with base ---> carbonate 

- act also as ligand (molecule donating e)

Uses

- fire retardant

- reactant in producing Na2CO3

- producing carbonated drink 

- carbon cycle-biofuel

 

Carbonate

- don’t dissolves in water except from group IA

Structure

- planar sp2, exist as resonance

 

Halide

- doesnt undergo hydrolysis because Carbon has no d

 Orbital to receive a pair of electron form water

CCL₄

Preparation

       CS₂ + 3Cl₂ ----> CCl₄ + S₂Cl₂

 

CF₄

Properties

-inert, non-toxic, non-corrosive

-generally volatile

-insoluble

- dissolves in CCl₄, CHCl₃

- the high stability and inertness is due to 

Uses

- freon (refrigerating gas), moomer in making plastic,

 Non-stciky utensil

 

Carbide(C + metal)

- ionic carbide ( C + group IA, IIA, IIIA)

- easily hydrolize

-covalent carbide (SiC, B₄C)

- giant molecule having covalent bonding 

 (B₄C has icosahedral B12 units alternating with C3)

(SiC has tetrahedral lattice and can exist in two forms 

corresponding to wurtzite and sphalerite lattices)

- inert and hard substances

- used for making cutting tools

- SiC is an insulator but B4C is metallic in appearance as 

well as in properties even though it is covalent carbide

- interstitial carbide

- C are adsorbed into metallic lattice interstices

- have non-stoichiometric composition

- eg (Mn₄C , Mn₅C)

Properties

-lustrous solids with metallic properties 

-have high melting points (TaC = 4170 K) and 

extremely hard solids but brittle. 

-Chemically inert and are hydrolysed by steam only above 

870 K 

 

SILICON

- exist as sand / flint

- silicate substances

 

Extraction

- Reducing SiO2 by coke 

 - using electric furnace

 - excess silica used to prevent formation of Sic

- I) Reducing SiCl4 by Na

- ii) zone refining process

 

Characteristic

- crystalline Si has metallic luster

- diamond lattice

- High mp

- inert element

- not dissolve in acid except HF

- dissolve in base

 

COMPOUNDS

Oxides

- SiO2 (silica)

- exist as polymeric tetrahedral

- 50% ionic due to difference in electronegative

- as a molecule, its a covalent macromolecule

Preparation

- Hydrolysis of SiCl4

- acidification of water glass

Characteristic

- inert at low temp

- become strong acidic oxide at elevated temp

- dissolve in HF only and alkali

 

Silicate

- SiO2 + (m oxides/m sulphate/ m carbonate)

- structure, polymorph

Aluminosilicate

- 3D silicate

- Occur when Al atom substitute Si

- framework become negatively charge

-eg (Felaspar, Zeolite)

Zeolite

- regular size of pores and channels

- act as molecular sieves to separate molecules of different size

- cation balancing framework can be exchangeable

 

Silicate Glass

- sand + (m silicate/aluminosilicate/borosilicate)

Characteristic

- not a true solid

- has no mp

- heating --> soften ---> semisolid ---> clear liquid

- inert except F2

- produce soda glass

 

Type Of Glass

- soft glass

  - ordinary soda lime

  - easily fusible glass

  - used for making bottles, windows

- hard glass

  - potash lime-glass

  - used for apparatus

  - resistant in chemicals

- Flint glass

  - lead- potash-lime glass

  - high refractivity

  - used in making lenses

- Jena glass

  - zinc-barium-borosilicate glass

  - low thermal expansion

  - used fro heat shock resistent apparatus

 - Pyrex

  - sodium-aluminium-borosilicate

  - similar to Jena

- Crooke’s glass

  - cut off UV ray

  - whole CaO replaced by PbO,BaO,ZnO,Mgo

- Quartz glass 

  - pure silica

  - not crack even red hot vessel is plunged straight into water

- Ground glass

  - soft glass

  - the surface has been grounded by emery

- Reinforced glass

  - has net work wires embedded in it

  - does not shatter easily

 

Silicones 

- organosilicon having heterocatenated Si-O-Si-O bonds

In chains, rings, branches

- consist Si-O-Si-O with alkyl/aryl bonded to Si

Preparation

- hydrolysis of alkyl/aryl silicon to halides followed by condensation

Types

- Disilicon (R3SiX)

- chain silicon (R2SiX2)

- branched silicon (RSiX3)

Properties

- thermally stable, low viscosity, remain elastic at low temp, inert towards chemical attack

Used

- Lubricant, cosmetic, breast implant, wax on car surface

Halides

- silicone halides, SiX4

- all halides except SiF4 unstable and undergo hydrolysis
- SiF4 undergo partial hydrolysis

Hydrides

- silanes

- form catenation, SiH4,Si2H3….up to Si6H14

Preparation

- stock’s reaction (silanes separated by fractional distillation)

Properties

- exist in gas, volatile liquid

- burn in air

- hydrolysis in water and alkali

 

TIN (Sn)

Preparation

 - extraction of Tin Ore(SnO2)

Tin allotrope

 - alpha-Sn (grey)

 - beta -Sn (white)

 - gamma-Sn

(transformation temperature will change the allotrope)

Physicochemical properties

- soft, malleable, not very ductile, brittle in heationg, crackles when bent

 
COMPOUND OF TIN

Oxides (SnO, SnO2)

- SnO2

  - preparation

- direct heating of metal in O2

  - pure ionic oxide

  - not dissolve in Hcl, HNO3, aqua regia

  - amphoteric acid

-SnO

  - black tin

  - preparation

     - melting of tin oxalate

  - amphoteric oxide

 

Halides

- SnCl4

  - preparation

- direct heating of Sn, Cl2

  - colourless liquid

  - covalent compound

  - rapidly hydrolyzed and fuming when in moist air

  - form complex with HNO3

- SnCl2

  - predominantly covalent compound 

  - soluble in water, inorganic solvent

  - preparation 

- anhydrous SnCl2

- Hydrated SnCl2.2H2O

  - anhydrous salt is transparent crystalline solid

  - dissolved in water to give cloudy solution

  - heating SnCl2.2H2O to form basic chloride

  - strong reducing agent

 

Sulfides

-SnS

  - obtained by passing through H2S gas in Sn(ii)

  - Dark brown unstable solid

  - easily oxidized to SnS2

- SnS2

  - obtained by oxidation of SnS using ammonium polysulfides

  - yellow solid

  - dissolve in excess ammonium polysulfides

 

LEAD (Pb)

- exist as mineral-galena

- extraction - roasting PbS with O2

          - PbO + C

- physicochemical properties

  - high density, high luster, ductile, malleable

 
COMPOUND OF LEAD

Oxides

- PbO

  - preparation

- direct reation of Pb + O2

- thermal decomposition of PbCO3

  - yellow solid

  -amphoteric acid

-PbO2

  - preparation

- heating of Pb(ii) with sodium chlorate

- read lead with nitric acid

  -properties

- dark /  black powder

-strong oxidizing agent

- ionic compound

- decompose when heating

- dissolve in acid

- amphoteric oxides

  - uses (as cathode in lead acid battery)

- Pb2O3

   - red lead

   - preparation

     - direct reaction excess 3Pb + O2

     - heating of PbO2

   - show properties as PbO and PbO2

   - uses (as pigment in paint to protect from rusting)

 

Halides

- PbX4

 - PbF4, PbCl4

 - Br and I not exist as its not strong reducing agent

 - exist in ionic form

Carbon Allotrope :-

Oxides : 
-Exist as CO2 and CO
-CO - Toxic , colourless and does not smell gas .
-CO2-colourless gas and does not smell and an hydride acid when dissolve in water. 
Carbonate : 
- Structure of C is sp2 and exist as resonance. 
Halides :
- Does not undergo hydrolysis due to C has no d-orbital to receive electron from water. 
Carbides :

- Exists as SiO and silicate substances 
- Extraction 

- Characteristic - metallic luster and grayish colour, have diamond lattice , high melting point, does not dissolve in acids except HF .
Oxides :
-Exists as polymeric tetrahedral SiO2
-Strong acidic oxide.
- Silicate, Aluminosilicate ( Feldspar and Zeolite) , Silicate glass and silicones.
Halides :
- Unstable and undergo hydrolysis except SiF4.
- Silanes

Tin
-Extraction : Reduction of Tin Ore with anthracite. 
-Tin allotrope :- 

Oxides :
-Exist in SnO2 and SnO
SnO2 - pure ionic oxide , does not dissolve in HCl , HNO3 or aqua regia
SnO- referred as black tin , amphoteric oxides but more Lewis basic .
Halides :
- Exist in SnX2 and SnX4 ( SnX2 is more stable than SnX4)
SnCl4- colourless liquid , covalent compound with tetrahedral
SnCl2 - covalent compound , soluble in water and organic solvent.
Sulfides :
-Exist as mono, SnS and disulphate, SnS2.
SnS- dark bown in colour , unstable solid , easily oxidize to SnS2,
SnS2 - yellow solid .

Lead 

- Exist as mineral (galena , PbS) 
- High density , soft and low boiling point . 
Oxides :
- Exist as PbO, PbO2, Pb3O4
PbO - yellow solid 
PbO2 - dark brown solid / black poweder , ionic compound , strong oxidizing agent , dissolves in acids. 
Pb3O4 - red lead 
Halide : 
- Pb(II) halide is more stable than Pb(IV) 
- Exists in PbF4 and PbCl4
- Ionic form 

1)Diamond in earth crust from crystallization molten magna.
Synthesized from graphite
(covalent, high mp, sp3, not conduct electric in molten n solid bcs no free e means all valence e used in covalent bond)
2)Graphite (Acheson Process high temp electrical furnace)
Soft, conduct electric, lubricant, oxidising agent /reducing agent
3)Fullerane
C60 : sp2,, from graphite, superconducter wire
4)Compound 
⚪Oxides CO2 and CO
⚪Carbonate 
⚪Halides 

⚪Carbides 

    1)Reducing SiO2 by Coke in     electrical furnace (high temp)
               +
excess Si (prevent SiC formed)
   2)Obtain Pure Si
      i) Reducing SiCl4 by Na
      ii) zone refining process
⚪Metallic luster, grayish color, high mp, inert when attacked by halogen, doesn't dissolve in acid but dissolve in HF, dissolve in base
⚪Silicon Oxides = Silica
B) SILICATE (SiO4)4-
⚪SiO2+metal Oxides /sulphate)/carbonate
⚪Polymorph structure
⚪Aluminisilicate(3D silicate, negatively charge, neutralised by cation gp IA, IIA)
-Feldspar
-Zeolite (detergent softener, separate gases,)
⚪Silicate glass [not true solid, supercooled liquid, no mp mean amorphous, heating soften, turn semisolid to clear liquid, inert( when attacked F2, HF, alkali).  ]
Soda glass form mix CaSiO3

C) SILICONES
⚪organosilicon
Si-O-Si-O (chain, rings, branches)
⚪Prepared by
1)Hydrolysis of alkyl /aryl halides followed
2)Condensation
⚪Types of silicone

⚪Compound
1)Silicon halides  EXC SIF3- unstable, and hydrolysis in water
2)hydride silicon(silanes) form Catenation 
-Prepare stock's reaction  then 
fractional distillation to separate Silanes

⚪Extract
     1)roasting SnO2(impurities S,As)
     2)reduction of SnO2 by C to Sn
     3)purification Of Sn
     - by electrolysis or melting
        Sn pure in cathode
        SnO2 impure in Anode
⚪Tin allotrope

⚪Compund of Sn
A) OXIDES
SnO2(+r4)
SnO(+2)
B)HALIDES
SnCl2(+2) more stable than SnCl4(+4)
C)SULPHIDE
SnS - dark brown
SnS2 - yellow

⚪Mineral galena, PbS
⚪Extract 1)roast PbS by CO2
                 2) C added
⚪Compund
A) OXIDE
-PbO (+2), yellow
-PbO2(+4)
brownish solid, black powder
-Pb3O4(mixture 2PbO. PbO2)
Uses of Red lead, red pigment in paint:
protect iron and steel from rusting
B) HALIDE
Pb(II) halide more stable 
than Pb(IV) halide

Summary Group IVA:
- has valance electron ns2 np2
- oxidation number +2 down the group become more stable due to inert pair effect while for +4 decrease down the group
- Inert pair effect : for oxidation number +4 to +2

-Allotrope:
 : C (diamond, graphite, fullerence, nanocarbon)
 : Sn (alpha-Sn, beta-Sn)

-Strength of covalent bonding:
 : no non-bonding electron-decrease down the group
 : has non-bonding electron-increase (C --> Si), decrease (Sn --> Pb)

Catenation
-decrease down the group
-C has greatest tendency and form stable hydrocarbon (good overlapping ppi-ppi orbital)
-Si less stable (poor ppi-ppi overlapping-bcs large size)

Chemical properties
 -reactivity increase down the group
-oxygen ( oxides )
-sulphide ( sulphides )
-halides
-Acid (cold, no rxn) (hot, has rxn)
-alkali, OH-  --> (MO3)2- and H2
-metal
 C: carbides
Si: silicides
Ge, Sn, Pb: alloy (strong)

Oxides
CO
Preparation:
1. Dehydration formic acid by H2SO4
2. Reduction CO2 by hot-red
CO2
Preparation:
1. Rxn acid with calcium carbonate

Carbonates
- has carbonate and hydrogen carbonates
-does not dissolve in water execpt carbonate from grop IA

Halides
- does not undergo hydrolysis
- CF4: high stability and inertness due to high bond energy
- Freon: refrigerating gas
- Perflurovinilchloride: making plastics
- Polytetrafluoroethene: non stick cooking utensil

Carbides
- C+Metal
: ionic carbides (saline carbides)
: covalent carbides (metalloid carbides)
: interstitial carbides (metallic carbides)

Existance
- SiO2 (sand, quartz, flint, agate)

Extraction
1. Reducing SiO2 (sand)  by Coke
2. To obtain pure Si
 : reducing SiCl4 by Na
 : refining process

Characteristics
-crystalline -> metallic structure adn grayish color
-diamond lattice
-high melting point
- not dissolve in any acid excpt HF, dissolve in  base

Oxides
-silicon oxcides, SiO2 (silica)
Preparation:
1. Hydrlysis of SiCl4
2. Acidificaton water glass

 Silicate, (SiO4)2-
: + metal oxides / metal sulphates / metal carbonates
: structure, polymorph

 Auminosilicate
: Al substitute Si in silicate framework
: negatively charge
: eg (feldspar, zeolite)

Silicate glass
- sand + metal silicate / aluminosilicate / borosilicate
Characteristic:
-not  true solid
-supercooled liquid, high viscosity
-no melting point
-inert
Production:
1. mixture calsium silicate and sodium silicate
Type:
- Hard glass
- Soft glass
- Flint glass
- Jena glass
- Pyrex / corning glass
- Crooke's glass
- Quartz glass
- Groung glass
- Reinforced glass

Silicones
- Organo silicon compound contain heterocatenated Si-O-Si-O bonds
Preparation:
1. Hydrolysis of alkyl / aryl silicon halides -> followed by condensation
Types:
- Disilicone, R3SiX
- Chains silicone, R2SiX2
- Branched silicone, RSiX3

Silicon Halides, SiX4
- except SiF4, all halides unstable and undergo hydrolysis in water easily
 : SiF4 undergo partial hydolysis
- hydolysis occur -> formation dative bonding from O of water to Si of SiX4
- form catenation
Preparation :
1. Stock's reaction
2. SiCl4 + LiAlH4 ---> SiH +LiCl + AlCl3
Properties:
-exist in gas form
- butn in air spontaneously
-hydrolysis in water and alkali

Tin, Sn
Tin allotrope:
- alpha-Sn (grey) , beta-Sn (white) , gamma-Sn
: transformation temp. between allotropes
- Tin-Plague / tin-pest
: change from white (beta-Sn) to grey (alpha-Sn)

Physicochemical properties
- Soft, melleable, not nery ductile, brittles on heating, crackles when bent

Chemical prop.
1. O2
: form SnO2 on heating
2. Water / steam
: forms little H2 at high temp.
3. Chlorine
: forms SnCl4 on heating
4. Sulphur
: forms SnS / SnS2 depends on temp.
5. Hot conc. / molten alkalis
: forms H2 and Sn(OH)4,2-
6. Diluted acids
: very slow
7. conc. H2SO4
: forms Sn(SO4)2
8. conc. HCl
  : forms hydrated SnCl2
9. conc. HNO3
; forms hydrated SnO2

Oxides (SnO2, SnO)
SnO2
- Direct heating in air / oxygen
pure ionic oxides
- not dissolves in HCl, HNO3 / aqua regia
- Amphoteric oxides
: H2So4
: OH-
SnO
- black tin
- Preparation
: Heating tin oxalate
- Amphoteric oxides

Halides
SnCl4
Preparation:
1. direct heating
- Colorless liquid
- Covalent compund
- In moist air, rapidly hydrolyzed and fuming
- rxn with conc. HCl / NH4Cl, form complex SnCl6, 2-
SnCl2
Preparation:
1. Anhydrous SnCl2
2. Hydrated SnCl2.2H2O
- Predominant covalent compound
- Soluble in wates & organic solvents
- Anhydrous salt is transparent crystaline solid
- Dissolved in waater
- Strong reducing agent

Sulfides
- Exist as mono (SnS) & disulphide (SnS2)
SnS
- Obtained by passing through H2S gas in Sn(II) sltn.
- Dark brown unstable solid
- easily oxidized to SnS2
SnS2
- Obtain by oxidation of SnS using ammonium polysulfides
- Yellow solid
- Dissolved in excess of (NH4)2Sx

Lead, Pb
- mineral-galena, PbS

Physicochemical properties
- High density, soft, low boiling point
- High luster, ductile & hugh melleable
- Resist corrosive

Oxides
- PbO, PbO2 & Pb3O4
PbO : Lead oxides
Preparaton:
1. Direct reaction
2. Thermal decomposition Pb(NO3)2 / PbCO3
- Yellow solid
- Amphoteric oxides
PbO2
Preparation:
1. heating Pb(II) sltn with sodium chlorate
2. Red lead with nitric acids
- Dark brownish / black powder
- Strong oxidizing agent
- Ionis compound
- Dissolves in acids
- Decompose when heating
- Amphoteric oxides
Pb3O4
- Red lead
- Mixture of 2PbO.PbO2
- Sjow prperties like PbO and PbO2

Halides
- Pb(II) halides more stable than Pb(IV) halide
PbX4
- PbF4 & PbCl4 exists
- PbBr4 & PbI4 does not exist --> not strong oxidizing agent
PbX2
- All halides exist in ionic form

- C -> great tendency, Si -> less stable. (poor pπ overlapping - large size)
- Increased reactivity going down
- Form compounds: oxides, sulphides, halides.

Carbon
- Many allotropes (eg. diamond, fullerene, graphite)
- Diamond: bonded by covalents, high mp, each C bond with other 4 C, no free e^-. uses: precious jewelry, cutting tool
- Graphite: prepared by Acheson Process, 2-D C sheets, soft (weak bonds between layers), conducts electricity, oxidizing agent
- Fullerene: big C framework of even numbers, aka. bucky ball, truncated icosahedrons = soccer ball (C₆₀), very stable, similar reaction to alkenes
-Oxides: CO₂ & CO.
CO prep: dehydration of formic acid or oxalic acid by conc. H₂SO₄, reduction of CO₂. Prop.: colorless & scentless, burn with blue flame, toxic, strong reducing agent, ligand. Uses: prod. of pure Ni metal, steam reforming process, reagent to prod. phosgene
CO₂ prep.: react acid with calcium carbonate, heat limestone. Prop.: colorless & scentless, solid = dry ice, dissolve in H₂O = H₂CO₃, react with base = carbonate, ligand. Uses: fire retardant, Solvay process, prod. carbonated drinks & baking soda, carbon cycle-biofuel
CO₃^2- & HCO₃^- : insoluble except group IA, planar C, resonance.
- Halides: not go hydrolysis because no d-orbital. CCl4: organic solvent, CF4: Freon, F₂C=CFCl, PTFE
- Carbides: C + Metal,
ionic: IA, IIA & IIIA, easily hydrolyzed.
covalent: Si & B, giant molecules, inert & hard, cutting tool, SiC insulator B₄C metallic.
interstitial: transition metals, C absorbed into metallic lattices, lustrous solids, high mp, hard but brittle, inert

Silicon
- exist as compound
- extraction: reduce SiO₂, reduce SiCl₄ by Na, zone refining process.
- metallic luster & grayish color, diamond lattice, high mp, inert element except with halogen, dissolves in HF & bases
- oxides: SiO2. Prep.: hydrolysis of SiCl4, acidification of water glass. Char.: inert at low temp., strong acidic oxide at elevated temp., dissolve in alkali
- (SiO₄)^4-: SiO₂ + M oxides/sulphates/carbonates. struc.: polymorph
- Aluminosilicate: 3D silicate, Al subs. Si in silicate framework (becomes -tive, balanced by cations). eg.: feldspar, zeolite.
Zeolite: regular size of pores, molecular sieves, ion exchanger
- Silicate glass: not true solid (supercooled liquid), no mp (amorphous)
Types of glass: flint, pyrex, crooke, quartz, ground, reinforced
- Silicones: organosilicon compounds. Prep.: hydrolysis of alkyl/aryl silicon halides followed by condensation
Types: Disilicone (R₃SiX), Chain (R₂SiX), Branched (RSiX₃).
Prop.: thermally stable, low viscosity, silicone rubbers, hydrophobic (alkyl groups)
Uses: lubricants, low temp. hydraulic fluids, cosmetics, breast implants, wax
- Halides: all SiX₄. all unstable except SiF₄ (partial hydrolysis)
- Hydrides: form catenations. Prep.: Stock's reaction, separated by fractional distillation.
Prop.: exist in gas & volatile liquids, burns spontaneously, hydrolyze in water and alkali

Tin
- Extraction from cassitserite
- Allotrope: alpha, beta, gamma (changes with temp.)
- Prop.: soft metal, malleable, not very ductile, brittle when heated, crackles when bent. reacts with oxygen, water, chlorine, sulphur, hot/conc./molten alkalis, conc. acids.
- Oxides: SnO₂, SnO
SnO₂: prep. direct heat. ionic oxide. does not dissolve in acids, amphoteric.
SnO: prep. heating tin oxalate. more amphoteric than SnO₂.
- Halides: SnX₂ > SnX₄
SnCl₄: prep.: direct heating, colorless, covalent compound, hydrolyze and fumes rapidly in moist air, forms complex SnCl₆^2- with conc. HCl/NH₄Cl
SnCl2: covalent compound, soluble in both, prep. differs with anhydrous and hydrated.
Anhydrous is transparent crystalline. soluble, strong reducing agent.
- Sulfide: exists as mono or di, mono: prep. pass H₂S in Sn(II) solution, dark brown unstable solid, easily oxidize to SnS₂
di: prep.: oxidation of mono, yellow solid, dissolve in excess (NH₄)₂S_x

Lead
- exist as galena, extract by roasting followed by reacting with C, prop.: high density but soft & low bp, high lister, ductile & malleable, resist corrosion
- Oxides: PbO, PbO₂, Pb₃O₄
PbO: prep. direct reaction, thermal decomposition of Pb(NO₃)₂ or PbCO₃. yellow solid. amphoteric.
PbO₂: prep. heat Pb(II) solution with sodium chlorate, red lead with nitric acid. prop.: dark brownish solid or black powder, strong oxidizing agent, ionic compound, decompose when heated, dissolves in acid, amphoteric. uses: cathode in lead acid battery
Pb3O4: red lead, mixture of 2PbO.PbO₂, shows properties of both. Uses: red paint pigments
- Halide: PbF₄ & PbCl₄ exists (others are not strong oxidizing agents). all PbX₂ exists

carbon monoxide,(CO)
- dehydration of formic acid/ oxalic acid by concentration H₂SO₄
- reduction of CO₂ by hot-red
properties
- colourless gas, does not smell
- burned with blue flame
- toxic gas
- strong reducing agent
uses
- production of pure Ni using Mond process
- gas in the synthesis gas, in reforming process to produce fuel
- hydroformylation produce higher alcohol
- reagent to produce phosgene

carbon dioxide,(CO₂)
- reaction of acid with calcium carbonate
- heating of limestone
properties 
- act as ligand
- react with base
- dissolve in water

- all carbonate does not dissolve in water except Group IA
- Planar C & exist as resonance

- does not undergo hydrolysis ( C has no d orbitals to receive a pair of electron from water)
- CCl₄ : organic colvent
- CF₄ : freon

- compound of C + M (IA,IIA & IIIA)
- easily hydrolyze
covalent carbide(metalloid carbides)
- giant molecules having covalent bonding
- SiC : tetrahedral lattice
- B₄C : icosahedral B₁₂ units alternating with C₃
- both carbides extremely inert & hard substance
- Sic insulator, B₄C metallic
interstitial carbide(metallic carbides)
- atom carbons are adsorbed into metallic lattice interstices
- non stoichiometric composition

- 2nd most abundant element  in earth
extraction :
- reducing SiO by coke 
pure Si 
- reducing SiCl4 by Na
- zone refining process
characteristic:
- high melting point
- inert element but attack by hydrogen
- does not dissolve in acids (except HF)

silicon dioxide, SiO2
- polymeric tetrahedral
- Si-O 50% ionic(diff EN)
# hydrolysis SiCl4
# acidification of water glass
characteristic
- inert  at low temp
- strong acidic oxide at elavated temp
- dissolved in HF
- dissolved in alkali
silicate, (SiO4)4-
- SiO2 + metal (oxides/sulphate/carbonate)
aluminosilicate
- Al atom subs Si in the silicate framework
- framework become -ve charge
- excess charges balanced by cations from group IA & IIA / transition metals
example
1. Feldspar
2. Zeolite
siliicate glass
sand + metal silicate/ aluminosilicate/ borosilicate
silicones
- organosilicon compound having heterocatenated Si-O-Si-O bonds in chains, rings & branches
# hydrolysis of alkyl/ aryl silicon halides
type of silicone
1. Disilicone - initial R3SiX
2. Chain silicone - initial R2SiX2
3. Branched silicone - initail RSiX3
properties
- thermally stable
- silicones water repelent 
uses 
- cosmetics
- breast implant

- all SiX4 
- all halides (except SiF6)

- form catenation
# stock's reaction
properties
- hydrolysis in water and alkali
- exist in gas
- burn in air spotaneously

SnO2
- pure ionic oxide
- does not dissolve in HCl
- amphoteric oxide
SnO
- oxidation no :  +2
- black tin
- amphoteric oxide

SnX2 > stable SnX4
SnCl4
# direct heating element
- colourless gas
SnCl2
- covalent compound 
- soluble in H2O & organic solvent
# anyhdrous SnCl2 
# hydarated SnCl2.2H2O

monosulphide (SnS) & disulphide (SnS2)
SnS
# passing through H2S gas
- dark brown unstable solid
- easily oxidise
SnS2
# oxidation SnS with ammonium polysulfides

mineral galena, PbS
- high density, but soft with low boiling point
- high luster

# direct reaction
# thermal decomposition Pb(NO3)2/PbCO3
- yellow solid
- amphoteric oxides
PbO2
# heating Pb(II) solution with sodium chlorate
# red lead with nitric acid

Pb3O4
- red lead
- mixture of 2PbO.PbO2

Pb(II) > stable Pb(IV)
PbX4
- PbF4 & PbCl4 exist
- PbBr4 & PbI$ does not exist ( not strong oxidizing agent)
PbX2
- all in ionic form

thankyou Dr for today lesson <3
i've no question so far.

2.  SILICON

3.  TIN ,Sn

4. LEAD, Pb

Summary for Group IVA

-inert pair effect is non-participation of the outer most ns2 electrons in chemical bonding.

-Cartenation is the ability of an element to be bonded to one another to form long chain. 

-Carbon show greatest cartenation.

 

CARBON

-Diamond,Graphite, Fullerene is allotropy of carbon

-Oxides *exist as CO2 and CO

-uses of CO is production of pure Ni, Hydroformylation

-uses of CO2 is fire retardant, reactant in Solvay Process

-All carbonates does not dissolves in water except from Group IA

-Halides of Carbon does not undergo hydrolysis

-Carbides is compund of (C + M)

 

SILICON

-High melting point boiling point

-Bluish-grey metal sheen

-Does not dissolve in any acid (except HF)

-Silica produce from Si+O2

-Silica is high purity, resistent and transparency

-uses in glass, ceramic

-Silicone produced form reaction between Si,O2,C and H

-Silicone is high thermal resistance 

-uses in cosmetic, breast implant shell

 

TIN

-soft metal, malleable,but not ductile

-Oxides (SnO2, SnO)

-SnO is more basic than SnO2 because it has more electron.

-Halides (SnX2 is more stable than SnX4)

-Sulfide (Exist as mono and disulphide)

 

LEAD

-Oxide exist as PbO,PbO2,Pb3O4

-Pb3O4 or read lead is commonly used in  in painting to protect iron and steel from rusting

 

 

 

-Carbon does not affected by inert pair effect

-Inert pair effect is tendency of heavier atoms to form ions (with different charge) & use electron configuration to explain
-Carbon form allotrope which is diamond,graphite,fullerene, nanocarbon. 
-Catenation is ability bonded to one another.
-Carbon showed greatest tendency forming stable hydrocarbon chain & rings but Si less stable.
-High energy more stable.
-Down the group, increases reactivity 
CARBON 
Allotrophy 
1) Diamond 
-crystallization of molten magna in earth crust
-can synthesized from graphite 
-not easy process 
-as cutting tool, precious jewelry
2) Graphite 
-Acheson process 
-stacked of two-dimensional carbon sheets. 
-soft , weak bonds between layers
-conducts electricity 
-in pencils and lubricant 
-oxidizing agent
3) Fullerene 
-C60 - icosahedrons = soccer ball 
- delocalized in nature of graphite 
-carbon nanotube 
-very stable 
-superconductor wire
Silicon
- 2nd most abundant element 
-SiO2 (silica) , silicate substances 
-having diamond lattice 
-Does not dissolve in any acids (except HF) 
-dissolve in base
Compounds
-Oxides
polymeric tetrahedral
-Silicate 
polymorph , emerald, diopside, asbestos , mica 
-Silicon Halides 
-Aluminisilicate
Feldspar, zeolite 
Fire work
-Silicate Glass
Soft, hard, flint, jena, pyrex, crookes's , quartz ,ground, reinforces 
-Silicones
Tin 
Allotrope 
- alpha, beta, gamma 
-Tin -plague / tin-pest 
Oxides - SnO2, SnO 
Halides - SnCL4 
soluble both water and organic solvent 
Sulfide - mono (SnS) , disulphide (SnS2) 
Pb 
-mineral galena, PbS 
-high density but soft with low bp
-high luster, ductile , highly malleable 
-resists corrosive 
Oxides - PbO, PbO2 , Pb3O4
Halide - Pb (II) more stable than Pb (IV)

C(non-metal); Si, Ge(metalloid); Sn, Pb (metal)

Inert Pair Effect: non participating of outer most ns2 e-s(s orbital- better penetrating power) 

Strength Of Covalent Bonding (decreases from Si – Pb -> tends to form ionic bonding)

M-X

Catenation: ability of element bonded to one another -> long chain/ ring

Tendency decreases down group -> larger size -> poor overlapping ppi-ppi orbitals

Allotrope: C exist in >1 (bonding)form

Diamond: covalent, sp3(no free e-), high m.p

Production

1.      Crystallization of molten magna

2.      Synthesized from graphite

Graphite: covalent, electrical conductor, acts as both oxidizing & reducing agents(form intercalation compounds)

Fulllerene: big framework with even #C atoms

C60- bucky ball/buckmisterfullerene: stable(symmetry):       

CO: colourless (g), smelless, blue flame, strong reducing agent, acts as ligand(formation of carbonyl complexes)

Preparation

1.      Dehydration of formic acid/oxalic acid by {H2SO4}

2.      Reduction of CO2 by red hot C

CO2: dry ice (s), dibasic

CX4

Not undergo hydrolysis <- no d orbital

CCl4 - organic solvent

CF4(l) – high bond E ->inert, high stability, non-toxic, non-corrosive, insoluble in water alcohols, HF

Carbides: C + metal

e.g. SiC(insulator), B4C(metallic): inert, hard

Interstitial (metallic): non-stoichiometric compositions, metallic properties,chemically inert, hydrolysed by steam(>870K)

Si: inert but can be attacked by halogen, not dissolve in acid except HF, dissolve in base

Extraction

1.      Reducing SiO2(sand) by Coke ( electrical furnace under high temp.; must have excess SiO2 -> prevent SiC formation)  

2.      Obtain pure Si 

-reducing SiCl4 by Na

-zone refinining

SiO2(silica): polymetric tetrahedral, 50% ionic, covalent macromolecule as whole(polymorph)

Silicone: thermally stable, low viscosity, alkyl-> water repellent(hydrophobic), inert(chemical attack, oxidation), rubbers remain elastic at low temp.

1.      Disilicone – initial R3SiX

2.      Chain silicone – initial R2SiX2

3.      Branched – initial RSiX3

Silicon Halides: unstable

Form catention

Preparation

1.      Stock’s reaction

2.      SiCl4 + LiAlH4 -> SiH4 + LiCl + AlCl3

Extraction

Cassiterite(SnO2) -roasting-> SnO2 -reduction-> Sn -purification-> -electrolysis/melting-> anode:Sn(pure); cathode: SnO2(impure Sn)-reduction with anthracite C-> Sn + 2CO

SnS2: yellow

Exist as galena(PbS)

Extraction

2PbS + 2O2 -> 2SO2 + (2PbO -> + C)-> Pb + CO

PbO(lead oxide): yellow, amphoteric

Preparation

1.      Direct reaction with O2

2.      Thermal decomposition od Pb(NO3)2 or PbCO3

PbO2(lead dioxide): dark brownish solid / black powder, strong oxidizing agent, ionic, dissolve in acids, amphoeric

Preparation

1.      Heating Pb(ii) soln with NaCl

2.      Red Pb with HNO3

Cathode in lead acid battery

Pb3O4(trilead tetraoxide): red lead

Mixture of 2PbO.PbO2

Preparation

3Pb + O2 -> Pb3O4

PbO2 -heat-> Pb3O4 + O2

Halide: ionic