Question

An atom of element 'A' has 3 electrons in the outer most shell and that of B has 6 electrons in its outer most shell. The formula of the compound between these two will be is

• A. A3B6
• B. A2B3
• C. A3B2
• D. A2B

Answer 1

Answer:

B. A2B3

• Element A: It has 3 electrons in its outermost shell. To achieve a stable octet, it easily loses these 3 electrons, giving it a valency of 3.

• Element B: It has 6 electrons in its outermost shell. To complete its octet, it needs to gain 2 electrons, giving it a valency of 2.

• Applying the criss-cross method to combine their valencies:

• The valency of A (3) becomes the subscript for B.

• The valency of B (2) becomes the subscript for A.

• This combines to form the formula A₂B₃