Question

An element belongs to group III. What
is it's valency? Write the molecular
formula of the compound when it reacts with element Y of group VA and Z of group VIIA.​

Answer 1

Answer:

Valency 2.

VA Mg

2+

Mg

−3

Mg

3

VIA

Symbols Valencies

Magnesium Oxide Magnesium Oxide

Mg O 2

+

2

−

(i) Write the symbols

On the left hand side On the right hand side

Calcium Chloride

Ca Cl

(ii) Write the valency of the symbols

At the top right corner At the top right corner

Positive ion Negative ion

Ca

2+

Cl1−

(iii) Interchange the valency number

(Ignore the (+) and (-) signs)

Ca

2+

Cl

1−

1 2

(iv) Write the interchanged numbers at the base

But ignore the + and the - signs

Ca

1

Cl

2