Question

Based on the group valency of elements state the formula for the following
giving justification for each:
a. Oxides of 1st group elements,
b. Halides of the elements of group 13, and
c. Compounds formed when an element of group 2 combines with an element
of group 16.
​

Answer 1

Explanation:

The elements in a group tend to have similar physical and chemical properties because of their similar outer shell electron structure.

1. Valency of first group elements is 1 and that of oxygen is 2. Hence, oxide of first group is X

2

O.

Eg; H O

1 2 (Criss cross)

H

2

O is the oxide.

2. Group 13 has a valency of 3 and that of halogen is 1. Hence, halide of group 13 is MX

3

Eg; B Cl

3 1 (Criss cross)

BCl

3

is the halide.

3. The valency of the Group 2 elements is +2 and that of Group 16 elements is -2. Group 2 loses electrons and group 16 accepts electrons. Hence, compounds formed are MY.

Eg; Mg O

2 2 (Criss cross)

MgO is the compound.

hope it helps u ❤️❤️

Answer 2

Answer:

a.

H2O, Li2O, Na2O ,K2O ,Rb2O

b.

BX3,AlX3,GaX3 (where X is F-( fluoride) , Cl-(chloride) , any halide .)

c.

the valency of group 2 element is 2 and the valency of group 16 elements is also 2

compounds are BeO MgO, CaO ,