Question

State the followings as true (T) or false (F):

(a) The electronic configuration of magnesium is 2, 8, 2. So its valency is 2.
(b) Atom attains stability when it achieves the noble gas configuration.
(c) Number of electrons in an atom = Mass number​

Answer 1

(a) The outermost shell of magnesium contains only 2 electrons hence, its valency is 2. So, the statement (a) is true.

(b) Atom attains stability when it achieves the noble gas configuration by losing, sharing or gaining electrons to and from another atom. So, the statement (b) is true.

(c) Mass number is equal to sum of number of protons and neutrons. Atomic number of an neutral atom is equal to number of electrons. So, the statement (c) is false.