Question

An element A reacts with oxygen to form A2O. (a)State the number of electrons in the outermost orbit of A.
(b)To which group of the periodic table does A belong?
(c)State whether A is a metal or a non-metal.

Answer 1

(a) Either 1 or 7 because the valency of A is 1 as we should cross multiply the valency so the answer is 1 .

(b) Hydrogen

(c) A that is hydrogen is a non - metal because it doesn't corrode on exposure to moisture , doesn't provide sonorous sound on being hit , it doesn't have lustrous capacity , it is not malleable or ductile . The above given properties are of metals which is not possessed by hydrogen .

Answer 2

a) The no. of electrons in the valence shell is 1.
b) It belongs to group 1.
c) It is a metal since it belongs to group 1.