Question

Which of the following elements shows $+7$ oxidation state?

• A. Manganese
• B. Boron
• C. Carbon
• D. Oxygen

Answer 1

The correct option is A

Manganese

The explanation for the correct option:

Option (A) Manganese

Oxidation state or oxidation number

• It is the total number of electrons that an atom either gains or loses in order to form a chemical bond with another atom.

Electronic configuration

• The electron configuration of an element describes how electrons are distributed in its atomic orbitals.

The oxidation state of Manganese

• The electronic configuration of Manganese is: $\left[\mathrm{Ar}\right]3{\mathrm{d}}^{5}4{\mathrm{s}}^2$
• The electrons present in the d and s subshell participate in the bond formation.
• Manganese can lose these electrons to form chemical bonds.
• Thus, Manganese shows variable oxidation states of +2, +3, +4, +5, +6, and +7.
• Hence, this option is correct.

Explanation of incorrect options:

Option B: Boron

• The electronic configuration of Boron is: $\left[\mathrm{He}\right]2{\mathrm{s}}^{2}2{\mathrm{p}}^1$
• The electrons present in the p and s subshell participate in the chemical reaction as after losing these electrons the boron atoms form a stable electronic configuration.
• Hence, boron shows an oxidation state of +3.
• Therefore, this option is incorrect.

Option C: Carbon

• The electronic configuration of carbon is: $\left[\mathrm{He}\right]2{\mathrm{s}}^{2}2{\mathrm{p}}^2$
• The electrons present in the p and s subshell participate in the chemical reaction as after losing these electrons the boron atoms form a stable electronic configuration.
• Hence, carbon shows an oxidation state of +4.
• Therefore, this option is incorrect.

Option D: Oxygen

• The electronic configuration of carbon is: $\left[\mathrm{He}\right]2{\mathrm{s}}^{2}2{\mathrm{p}}^4$
• There are two unpaired electrons in the p subshell, the oxygen atom readily loses these two electrons to form a relatively stable electronic configuration.
• Hence, oxygen shows an oxidation state of +2.
• Therefore, this option is incorrect.

Hence, option A, Manganese, is the correct answer.