MCQ
Ionisation energy in group $I-A$ varies in the decreasing order as
- ✓$Li > Na > K > Cs$
- B$Na > Li > K > Cs$
- C$Li > Cs > K > Na$
- D$K > Cs > Na > Li$
✓
Answer
Correct option: A.
$Li > Na > K > Cs$
a
(a) Due to the large size of group $IA$ elements, the outermost electron is far from the nucleus and can easily be removed. their ionisation energies or ionisation potentials are relatively low.
(a) Due to the large size of group $IA$ elements, the outermost electron is far from the nucleus and can easily be removed. their ionisation energies or ionisation potentials are relatively low.
$Li$, $Na$, $K$, $Rb$ , $Cs$
Ionisation potential $(eV) 5.4, \,\,5.1,\,\, 4.3,\,\, 4.2,\,\, 3.9$
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