Question

(a) Why are all atoms other than noble gas atoms, reactive? 

(b) Why a molecule of hydrogen is more a stable than the uncombined atoms?

Answer 1

(a) All atoms other than noble gas atoms are reactive because they are short of octet in their outermost shell. 

(b) When a molecule of hydrogen is obtained from the atoms, energy (104 kcal/mol) is released. Do, the molecule of hydrogen possesses lower energy than the atoms. Hence hydrogen molecule is more stable the uncombined atoms