Question

Which of the following has a octet/duplet electronic configuration?

• A. $B^{3-}$
• B. $B^{-}$
• C. $B^{3+}$
• D. $B^{2+}$

Answer 1

The correct option is C $B^{3+}$

The atomic number of Boron $=5$
Electronic configuration of Boron is: $\left[He\right]2s^{2}2p^1$
Configuration of valence shell: $2s^{2}2p^1$
It does not have a complete octet.

a) $B^{3-}$
Electronic configuration of $B^{3-}$ (with 8 electrons) is: $\left[He\right]2s^{2}2p^4$
Configuration of valence shell: $2s^{2}2p^4$
It does not have a complete octet.

b) $B^{-}$
Electronic configuration of $B^{-}$ ( with 6 electrons) is: $\left[He\right]2s^{2}2p^2$
Configuration of valence shell: $2s^{2}2p^2$
It does not have a complete octet.

(c) $B^{3+}$
Electronic configuration of $B^{3+}$ (with 2 electrons) is: $\left[He\right]$
Configuration of valence shell: $1s^2$
Boron is most likely to form $B^{3+}$ as it forms an inert gas electronic configuration of Helium (satisfying duplet).

(d) $B^{2+}$
Electronic configuration of $B^{2+}$ ( with 3 electrons) is: $\left[He\right]2s^1$
Configuration of valence shell: $2s^1$
It does not have a complete octet.