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Properties of period 3 elements [Zahra & Umairah]

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Properties of period 3 elements [Zahra & Umairah]

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Period 3 elements are Na, Mg, Al, Si, P, S, Cl to Ar

Atomic number ranges from 11 to 18

Have 3 electron shells

The metals change from metals Na, Mg, Al to metalloids (Si) to non-metals that are P, S, Cl, Ar.

Structure of Period 3 elements

The structure of the elements also change across

P, S, Cl and Ar form simple molecules

Si forms a giant covalent structure

Na, Mg and Ai form metallic structures

Metallic Structure: Strong attraction is present.

Giant covalent structure: Strong covalent bonds between atoms.

Simple molecules: Weak Van der Waals forces between molecules.

Melting and boiling point

Na, Mg and I have high melting and boiling point [strong metallic bonding]

Si has high melting and boiling point due to strong covalent bond

P, S and Cl are simple molecules [Van der Waals]. Have the lowest melting and boiling point

Electrical conductivity

Na, Mg and AI conduct electricity because of delocalized electron and electron are move freely

Si is a semiconductor and conduct at high temperature. No free electron at room temperature

P, Cl, CL and Ar do not conduct electricity [simple molecules]

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Properties and reactions of period 3 chlorides [Sofiya]

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Properties and reactions of period 3 chlorides [Sofiya]

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Properties :

Cl has a negative oxidation number which is -1

The oxidation state is the same as the number of electrons in the valence shell of the period 3 element.

Bonding and structure:

Bonding :

NaCl and MgCl2 (strong ionic bonding between cations and anions)

AlCl3, SiCl4, PCl5 (Weak intermolecular forces of attraction between molecules)

Structure :

NaCl and MgCl2 (Giant ionic lattice)

AlCl3, SiCl4, PCl5 (Simple molecular)

Reactions :

Reaction with water

NaCl does not react with water, it dissolves in water to give a neutral solution

MgCl2 reacts with water to give a faintly acidic solution (The Mg2+ pulls electrons from the O in H2O molecules towards it which makes the H in H2O slightly positive to be pulled off by H2O, forming H3O+ which is acidic.

Solid AlCl3 reacts violently with water, producing steamy fumes of hydrogen chloride gas. An acidic solution is formed when solid AlCl3 is added into excess of water.

AlCl3 reacts with water to give an acidic solution, and Hexaaquaaluminium ions are formed. The 3+ charge on the Al pulls electrons from the O in H2O molecules strongly towards it. This makes the H in H2O more positive and easier to remove, amking it more acidic.

SiCl4 reacts with water violently, producing silicon dioxide and fumes of hydrogen chloride. In large excess of water, the hydrogen chloride will dissolve to give a strongly acidic solution containing hydrochloric acid.

PCl5 reacts violently with water, producing fumes of hydrogen chloride. If there is enough water present, these will dissolve to give a solution containing HCl.

With cold water, phosphorus oxychloride, POCl₃, is produced along with HCl.

With boiling water, phosphorus (V) chloride reacts to give phosphoric (V) acid and more HCl.

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Properties and reactions of period 3 hydroxides [Li Ying]

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Properties and reactions of period 3 hydroxides [Li Ying]

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Sodium hydroxide (NaOH)

Reaction with acid

forming salt

NaOH (aq) + HCl (aq) --> NaCl (aq) + H₂O (l)

Magnesium hydroxide (Mg(OH2))

Reaction with acid

forming salt

Mg(OH)₂ (s) + 2HCl (aq) --> MgCl₂ (aq) + 2H₂O (l)

Aluminium hydroxide (AI(OH3)) - amphoteric

Reaction with hydrochloric acid

forming aluminium chloride

Al(OH)₃ (s) + 3HCl (aq) --> AlCl₃ (aq) + 3H₂O (l)

Reaction with sodium hydroxide

Forming sodium tetrahydroxoaluminate (colouless solution)

Al(OH)₃ (s) + NaOH (aq) --> NaAl(OH)4 (aq)

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Properties and reactions of period 3 oxides (Raam)

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Properties and reactions of period 3 oxides (Raam)

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Properties:

Bonding

Na2O, MgO and Al2O3 (metals) have ionic bonds in their ionic lattice

SiO2 (metalloid) has covalent bonds their giant covalent structure

P4O10 and SO3 (non-metals) have covalent bonding and weak intermolecular forces (Van Der Waal’s forces of attraction)

Structure

From metals (Na2O, MgO and Al2O3) to metalloids (SiO2) to non-metals (P4O10 and SO3), the structures change from giant ionic lattices to giant covalent structure to simple molecular structures

Reactions:

1. Reactions of Na₂O:

1. Sodium oxide reacts with cold water to form sodium hydroxide

1. Na₂O(s) + H₂O (l)--> 2NaOH (aq)

2. Sodium oxide reacts with hydrochloric acid to produce sodium chloride

1. Na₂O (s) + 2HCl (aq) --> 2NaCl (aq) + H₂O (l)

2. Reactions of MgO:

1. Magnesium oxide reacts with water to form magnesium hydroxide.

1. MgO (s) + H₂O (l) --> Mg(OH)₂ (s)

2. Magnesium oxide reacts with warm HCl to produce magnesium chloride

1. MgO (s) + 2HCl (aq) --> MgCl₂ (aq) + H₂O (l)

3. Reactions of Al₂O₃:

1. Aluminum oxide is unreactive with water

2. Aluminum oxide reacts with warm HCl to produce aluminum chloride

1. Al₂O₃ (s) + 6HCl (aq) --> 2AlCl₃ (aq) + 3H₂O (l)

3. Aluminum oxide reacts with sodium hydroxide to produce sodium tetrahydroaluminate

1. Al₂O₃ (s) + 2NaOH (aq) + 3H₂O (l) --> 2NaAl(OH)₄ (aq)

4. Reactions of SiO₂:

1. Silicon dioxide does not react with water

2. Silicon dioxide reacts with sodium hydroxide to form sodium silicate.

1. SiO₂ (s) + 2NaOH (aq) --> Na₂SiO₃ (aq) + H₂O (l)

5. Reactions of P₄O₁₀:

1. Phosphorus (V) oxide reacts with water to form phosphoric (V) acid.

1. P₄O₁₀ (s) + 6H₂O (l) --> 4H₃PO₄ (aq)

2. Phosphorus (V) oxide reacts with sodium hydroxide solution to form sodium phosphate salt.

1. P₄O₁₀ (s) + 12NaOH (aq) --> 4Na₃PO₄ (aq) + 6H₂O (l)

6. Reactions of SO₃:

1. Sulphur trioxide reacts violently with water to produce a fog of sulphuric (VI) acid droplets.

1. SO₃ (g) + H₂O (l) --> H₂SO₄ (aq)

2. Sulphur trioxide reacts with sodium hydroxide solution to form sodium sulphate salt.

1. SO₃ (g) + 2NaOH (aq) ® Na₂SO₄ (aq) + H₂O (l)