When determining the formula for a compound, it is important to know the valence numbers of each element. suppose you want to write a formula for a compound with these two elements: element a = valence 3 element b = valence 2 in the formula, what number will be the subscript for element b?

Explanation:

The valency of the element is the measure of the combining power of the element with the other atoms when the element forms compounds or molecules.

Thus, valency has to known to find the how the elements have been combined and how many electrons have been lost, gain or shared.

Given that:

Element A has 3 valence electrons and element B has 2 valence electrons. To find the ionic compound, the valency of the cations and the anions are interchanged and are written in subscripts. Thus,

A        B

3          2

Cross multiplying, we get the formula :

Hence, 3 is the subscript for Element B.

periodic trends is an atom that gets larger as the number of electronic shells increase, the radius of atoms increases as you go down a certain group in the periodic table of elements. in general, the size of an atom will decrease as you move from left to right of a certain period.

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be