Any rearrangement of electrons in two atoms that generates a force, causing the atoms to be bound to each other, forming a molecule. 

Elements bond to become more stable.

Bonded elements have less energy.

When bonds are formed, energy is released.

As a result of bonding, the different elements in a compound will have full valence shells. (For most that is 8 electrons, or a full octet)

There are different types of bonds:

Ionic Bonding- metals and non metals; metals transfer valence electrons and will have a full inner kernel shell of electrons and non metals accept the electrons to fill their valence shell; metals become cations and non metals become anions; usually an electronegativity difference of 1.7 or greater

Covalent Bonding- A covalent bond is formed when two nuclei share electrons in order to achieve a stable arrangement of electrons.

Metallic Bonding- A metales bond results from the force of attraction of the mobile valence electrons for an atom’s positively charged kernel.

How to write an ionic compound formula using the Periodic Table:

Look for number of valence electrons in each element

Find how many electrons are needed in the non metals 

Check oxidation state of both metal and non metal 

Write down chemical symbols with metal then non metal 

Criss cross oxidation states 

Table E on Reference Table 

Metals also combine with polyatomic ions 

Monoatomic ions=Na+, Cl-, K+, Fe+

Polyatomic ions=made of many 

Polyatomic ions will accept electrons from metals 

When an element has multiple oxidation states, you need to acknowledge the charge used when naming.

When bonds break, energy is absorbed.(endothermic)

 When bonds are formed, energy is released. (Exothermic)

1 valence 

Very active metals 

Not found unconvinced in nature 

As you go down a group the valence electrons are more active and reactive 

Silvery white in color 

Lose 1 valence electrons when they bond 

 

Group 2 is called the alkaline metals 

They’re metals 

2 valence electrons 

When they bong they lose two valence electrons 

Solids at room temp 

They are also silvery/ white in color 

They’re not as reactive as group one 

They are rarely found uncombined

 Also known as heavy metals 

Tend to be very dense 

Varying reactivity because they have multiple oxidation states 

They have the ability to form more than one ion because of the multiple oxidation states 

The have colorful ions and solutions 

 

Halogens 

The only group that has elements in all three phases 

7 valence 

Highly reactive 

When they bond they gain an electron 

Fluorine is king of electronegativity (4.0) 

 

Noble gases 

Very stable because of full valence 

Usually do not react in the present of other elements 

Relatively inert 

Xe can react with F 

He is the only group 18 element without a full octet but still has a full valence 

They are all monoatomic molecules 

 

Lanthanide and actinide series 

Rare earth metals 

Above 92 are man made and unstable 

 

Reactivity in metals 

Atoms react when they gain lose or share electrons 

Metals lose electrons 

Across a period metal reactivity decreases 

Down a group metal reactivity decrease 

 

Reactivity in nonmetals 

Nonmetals gain electrons 

Across a period no metal reactivity increase (more protons so they attract more electrons) 

Down a group nonmetal reactivity decreases because of shielding 

Best metal is Francium 

Across a period metallic character decreases because there are more protons in the same energy level so there a tighter grip on electrons 

Down a group metallic character increases because shielding prevents a nucleus from holding electrons so the electrons become more free

Atomic radius: 

 

Metallic character 

 

Electronegativity: 

 

Ionization energy: 

 

Properties of nonmetals