Different (variable) oxidation state is shown by transition elements. It is due to the fact:
A. (n-1)d electrons may be excited to ns orbital
B. ns electrons may be excited to (n-1)d orbitals
C. (n-1)d electrons may get involved along with ns electrons in bonding
D. None of the above.

Question

Different (variable) oxidation state is shown by transition elements. It is due to the fact:
A. (n-1)d electrons may be excited to ns orbital
B. ns electrons may be excited to (n-1)d orbitals
C. (n-1)d electrons may get involved along with ns electrons in bonding
D. None of the above.

Vedantu Content Team · Accepted Answer

Hint: There are certain elements in the periodic table, which have partially filled d subshells. These elements can form cations with incompletely filled d orbitals. They are called transition elements.

Complete step by step answer:
Elements which are in group 3 to 12, including lanthanides and actinides come under the group transition elements. These elements come under the d-block and their general electronic configuration is \[{\text{(n - 1)}}{{\text{d}}^{1 - 10}}{\text{n}}{{\text{s}}^{1 - 2}}\]. These elements may have electrons in both ns and (n-1)d orbitals. The energy difference between these two orbitals is very small. So, while forming bonds, these elements first use ns electrons and then if required, (n-1)d electrons can also be used.
Hence, variable oxidation states are shown by transition elements due to the fact that (n-1)d electrons may get involved along with ns electrons in bonding.

So, option C is correct.

Additional information:
Each transition element shows a minimum and a maximum oxidation state. The minimum oxidation state corresponds to the total number of electrons in s subshell whereas, maximum oxidation state corresponds to the total number of electrons available in both ns and (n-1)d subshell. The number of oxidation states shown by transition elements are –

Elements	Outer electronic configuration	Oxidation states
Sc	\[{\text{3}}{{\text{d}}^1}{\text{ 4}}{{\text{s}}^2}\]	+2, +3
Ti	\[{\text{3}}{{\text{d}}^2}{\text{ 4}}{{\text{s}}^2}\]	+2, +3, +4
V	\[{\text{3}}{{\text{d}}^3}{\text{ 4}}{{\text{s}}^2}\]	+2, +3, +4, +5, +6
Cr	\[{\text{3}}{{\text{d}}^5}{\text{ 4}}{{\text{s}}^1}\]	+2, +3, +4, +5, +6,
Mn	\[{\text{3}}{{\text{d}}^5}{\text{ 4}}{{\text{s}}^2}\]	+2, +3, +4, +5, +6, +7
Fe	\[{\text{3}}{{\text{d}}^6}{\text{ 4}}{{\text{s}}^2}\]	+2, +3, +4, +5, +6
Co	\[{\text{3}}{{\text{d}}^7}{\text{ 4}}{{\text{s}}^2}\]	+2, +3, +4
Ni	\[{\text{3}}{{\text{d}}^1}{\text{ 4}}{{\text{s}}^2}\]	+2, +3, +4
Cu	\[{\text{3}}{{\text{d}}^{10}}{\text{ 4}}{{\text{s}}^1}\]	+1, +2
Zn	\[{\text{3}}{{\text{d}}^{10}}{\text{ 4}}{{\text{s}}^2}\]	+2

Note: Cr, Cu, Ag, Au and Hg are the elements which show minimum oxidation state of 1. Stability of oxidation states increases in the order 3d ˂ 4d ˂ 5d. 3d series elements are most stable in +2; 4d series in +2 and +4 and 5d series in +4.

Different (variable) oxidation state is shown by transition elements. It is due to the fact:A. (n-1)d electrons may be excited to ns orbitalB. ns electrons may be excited to (n-1)d orbitalsC. (n-1)d electrons may get involved along with ns electrons in bondingD. None of the above.

Repeaters Course for NEET 2022 - 23

Different (variable) oxidation state is shown by transition elements. It is due to the fact:
A. (n-1)d electrons may be excited to ns orbital
B. ns electrons may be excited to (n-1)d orbitals
C. (n-1)d electrons may get involved along with ns electrons in bonding
D. None of the above.