Question

Give reasons for the following:
(a) Isotopes of an element are chemically similar.
(b) An atom is electrically neutral.
(c) Noble gases show least reactivity.
(d) Ions are more stable than atom.
(e)Na+ has completely filled K and L shells.

Answer 1

A) they have same number of electrons and protons so they have similar chemical properties........ B)it is because they have same number of protons and electrons.......... C)they have completely filled valence shell...... D)because ions have octet configuration..... E)Na+ have 10 electrons so it has completely filled k And L shell

Answer 2

(a)isotopes are similar as they have same number of electrons  or electronic configuration.
(b)in an atom no. of electrons =no. of protons.as the  +ve and -ve charges are equal .atoms are electrically neutral.
(c)ions gain or loose electrons to attain octet.as they have stable octet configuration.ions are more stable than atoms.
(d)Na+ looses an electron to attain octet and thus have completely filled K and L shells.