Question

Arrange the following in increasing order of their size: $Be,Ca,Ba,Sr$.

• A. $Ca<Ba<Be<Sr$
• B. $Be<Sr<Ba<Ca$
• C. $Be<Ca<Sr<Ba$
• D. $Ba<Sr<Ca<Be$

Answer 1

The correct option is C $Be<Ca<Sr<Ba$

Atomic radii increases from top to bottom in the second group elements because principal quantum number $\left(n\right)$ increases and valance electrons are farther from nucleus. Electron shielding prevents the outer electrons from the nuclear attraction due to which atomic radius increases.
Therefore, correct increasing order of alkaline earth metals group is: $Be<Ca<Sr<Ba$