MCQ
Identify the elements having same valence shell.
- ✓$P$ and $Q$
- B$Q$ and $R$
- C$P$ and $R$
- D$P, Q$ and $R$
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Predict the value of $'X'$ is .............. $\mathrm{eV}$
(Molar mass of $Ca(OH)_2, Na_2SO_4$ and $CaSO_4$ are $74, 143$ and $136\, g\, mol^{-1}$ respectively; $K_{sp}$ of $Ca(OH)_2$ is $5.5 \times 10^{-6}$)