Question

two atoms X and Y have 5 and 7 Valence Electrons the formula of compound formed by the combination is

Answer 1

HELLO THERE!

Concept:

Elements having one to three valence electrons are metals, and  their valency is the number of valence electrons present itself!

Elements having more than three valence electrons are non metals and their valency is obtained by subtracting the number of valence electrons from 8.

In the given question, valence electrons present in X is 5, which is definitely greater than 3, so X is a non metal and its valency is 8 - 5 = 3.

Y has 7 valence electrons, which is again greater than 3. Y is also a non metal and its valency is 8 - 7 = 1.

So, X = 3, Y = 1, and while forming compound with two elements, we exchange the valencies.

So, when X and Y combine to form a compound, we get XY₃.

Example of such a compound is Nitrogen trichloride (NCl₃).

Valency of nitrogen is -3 and that of Chlorine is -1, and both are non metals.

THANKS!