Periodic Table, Periodic Properties and Variations of Properties — Chemistry STD 10 — Question
ICSE BoardEnglish MediumSTD 10ChemistryPeriodic Table, Periodic Properties and Variations of Properties1 Mark
MCQ
The elements having the least number of electrons shells :
A
Cs
B
K
C
Na
✓
Li
✓
Answer
Correct option: D.
Li
(d) Li Explanation : Lithium has the least number of electron shells. This is because period of an element corresponds to the number of the valence shell. $Li \Rightarrow 2^{\text {nd }}$ period 2 valence shells $Na \Rightarrow 3^{\text {rd }}$ period 3 valence shells
$K \Rightarrow 4^{\text {th }}$ period 4 valence shells
$Cs \Rightarrow 5^{\text {th }}$ period 5 valence shells Thus, lithium is the element having least number of valence shells, i.e, 2.
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