Question

Elements A, B, C and D have electronic configurations:

A = 2, 8, 1

B = 2, 8, 7

C = 2, 5

D = 1

1. What type of bond is formed between:
   1. A and B
   2. C and D
2. What is the formula of the compound formed between:
   1. B and D
   2. A and B

Answer 1

i.

1. An electrovalent bond forms when A donates 1 electron and B accepts it, and both attain a stable octet.
2. A covalent bond is formed as electrons are shared between C and D.

ii.

1. DB, as B needs one electron to complete its octet and D needs one electron to complete its duplet; hence, they both share one electron pair and form the DB compound.
2. AB, as A has the tendency to donate one electron and gain stability, whereas B has the tendency to gain one electron to be stable. Hence, A donates one electron, and B accepts it, forming the AB compound.