Question

First ionisation energy of alkali metals is very low but second ionisation energy is very high because.

• A. Alkali metals acquire noble gas configuration after losing one electron
• B. A large amount of energy is required to remove electron from a cation
• C. Alkali metals can form only univalent ions
• D. First group elements can lose only one electron.

Answer 1

Answer: (A)

Alkali metals acquire noble gas configuration after losing one electron

Answer 2

: Alkali metals attain noble gas configuration after losing one electron. It is very difficult to take out electron from a stable configuration.

$\underset{(Alkalimetal)}{M}\overset{\quad - le^{-}\quad}{\rightarrow}\underset{(Noblegas)}{M^{+}}$

e.g. $Na(2,8,1)\overset{\quad I.E.\quad}{\rightarrow}Na^{+}(2,8) + e^{-}$