2.3 Period 3 Elements

Question 1

Describe the reaction with sodium and water

Answer 1

Reacts vigorously to produce hydrogen gas and sodium hydroxide. Solution is strongly alkaline

Question 2

Describe the reaction of magnesium with water

Answer 2

Reacts slowly to produce hydrogen gas and magnesium hydroxide. Solution is weakly alkaline

Question 3

What forms when magnesium reacts with steam?

Answer 3

Magnesium oxide and hydrogen gas

Question 4

Oxide of sodium

Answer 4

Na2O

Question 5

Oxide of magnesium

Answer 5

MgO

Question 6

Oxide of aluminium

Answer 6

Al2O

Question 7

Oxide of silicon

Answer 7

SiO2

Question 8

Oxide of phosphorus

Answer 8

P4O10

Question 9

Oxide of sulfur

Answer 9

SO2

Question 10

How does phosphorus react in air?

Answer 10

Spontaneously combusts

Question 11

Which two elements produce no coloured flame and react slowly in air

Answer 11

Al

Si

Question 12

Why do the first three elments have high melting points?

Answer 12

They form giant ionic lattices which have strong forces of attraction.

Question 13

Why does aluminium oxide have a lower melting point than magnesium oxide?

Answer 13

The 3+ ions distort they oxygen’s electron cloud making the bond partially covalent

Question 14

Why do the oxides of phosphorus and sulphur very low?

Answer 14

They only have simple covalent structure with weak van der Waals forces between molecules

Question 15

Which oxides dissolve in water to make alkaline solitons

Answer 15

Magnesium and Sodium

Question 16

What kind of solutions do the oxides of phosphorus and sulphur form?

Answer 16

Strong acidic solutions

Question 17

What is special about aluminium oxide solutions?

Answer 17

Amphoteric so can act as either an acid or base