Q33 / 160 · TS EAMCET 2015 · Chemistry
An element in +2 oxidation state has 24 electrons. The atomic number of the element and the number of unpaired electrons in it respectively are
- A24 and 4
- Correct answerB26 and 4
- C24 and 2
- D26 and 5
Solution
$$
\begin{aligned}
& { }_{26} \mathrm{Fe}=1 s^2, 2 s^2 2 p^6, 3 s^2 3 p^6, 4 s^2, 3 d^6 \\
& { }_{26} \mathrm{Fe} \longrightarrow{ }_{26} \mathrm{Fe}^{2+}
\end{aligned}
$$
Hence, atomic number of iron $(\mathrm{Fe})$ is 26 and $\mathrm{Fe}^{2+}$ have 4 unpaired electrons in $3 d$-orbital.
Hence, the correct answer is option: 'B'.