Passage :

1) Covalent bond is formed when the combining atoms require 1, 2, 3 or 4 electrons to acquire the nearest noble gas configuration.

That means the combining atoms have 7, 6, 5 or 4 electrons in their outermost shell.

2) Covalent bond is formed generally between the two atoms which have same or almost same

Electro negativities.

Example : ${\text{F}}_2,\text{C}{l}_2,{\text{Br}}_2,\text{H}-\text{C}l$  etc.

Q. Covalent bond is formed between the two atoms if the difference in their electro negativities is