Inorganic Chapter 3: Period 3

Question 1

What element do period 3 elements readily react with?

Answer 1

Oxygen

Question 2

What usually happens when Period 3 elements form oxides?

Answer 2

They’re oxidised to their highest state - exception of Sulfur: it becomes SO₂

Question 3

Which is more reactive - Na or Mg?

Answer 3

Na - takes less energy to form a 1+ ion than a 2+ ion

Question 4

What is the trend in melting points across period 3?

Answer 4

MgO is higher than Na₂O, then they generally decrease from there.

Question 5

What is the structure of Na₂O?

Answer 5

Ionic

Question 6

What is the structure of SiO₂?

Answer 6

Giant Covalent

Question 7

What is the structure of P₄O₁₀?

Answer 7

Simple Covalent

Question 8

Are Ionic oxides acidic or alkaline?

Answer 8

Alkaline

Question 9

Are covalent oxides acidic or alkaline?

Answer 9

Acidic

Question 10

What is the general equation for neutralisation reactions?

Answer 10

Acid + Base -> Salt + Water

Question 11

What does Amphoteric mean?

Answer 11

It can react as either an acid or a base

Question 12

Why does MgO have a higher m.p. than Na₂O?

Answer 12

The 2+ bonds are stronger than the 1+ bonds

Question 13

Why does Al₂O₃ have a lower m.p. than Na₂O?

Answer 13

Because the difference in electronegativity between Al and O isn’t as big as between Mg and O, or Na and O, making it partially covalent.

Question 14

What is the equation for the formation of Phosphoric (V) acid from phosphorus (V) oxide?

Answer 14

P₄O₁₀ + 6H₂O -> 4H₃PO₄

Question 15

What is the equation for the formation of sulfuric (IV) acid from sulfur dioxide?

Answer 15

SO₂ + H₂O -> H₂SO₃

Question 16

What is the equation for the formation of Sulfuric (VI) acid from sulfur trioxide?

Answer 16

SO₃ + H₂O -> H₂SO₄

Question 17

What is an example of an amphoteric oxide?

Answer 17

Al₂O₃