Question

Maximum and minimum IP values in 3 d series are in:
A. Cr, Zn
B. Sc, Cu
C. Cu, Zn
D. Zn, Sc

Answer 1

Hint: ionization potential is the energy required for the removal of an electron from the outermost shell of an isolated gaseous atom. The atom having high charge density and small size require more energy to ionize. The atom having low charge density and large size require less energy to ionize.

Complete Step by step answer: Ionization potential is defined as the energy required for the removal of an electron from the outermost shell of an isolated gaseous atom. It is also known as ionization energy.

On going left to right in a period, the ionization potential increases.
The reason for increases in ionization potential is as follows:
-Increase in effective nuclear charge
-Decreases in size.
-Due to both of these factors, (increase in effective nuclear charge and decreases in size) the stabilization of the outermost shell increases, so it becomes hard to remove an electron from the outermost shell on going left to right in a period.

On going down in a group, the ionization potential decreases.
The reason for decreases in ionization potential is as follows:
-Decrease in effective nuclear charge
Increases in size.
-Due to both of these factors, (decrease in effective nuclear charge and increases in size) the stabilization of the outermost shell decreases, so it becomes easy to remove an electron from the outermost shell on going down in a group.
From left to right the $3$d series is shown as follows:
Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn.
Scandium is the top left element of the $3d$ series so it has the largest size and minimum effective nuclear charge so it can lose electrons easily, so its IP is minimum.
Zinc is the top right element of $3$d series so it has the smallest size and maximum effective nuclear charge so it cannot lose electrons easily, so its IP is maximum.

Therefore, option (D) Zn, Sc is correct.

Note: On going left to right in a period, the electrons are added in the same shell and the proton number also increases, so the attraction of the nucleus on the outermost shell increases. So, the size of the atom decreases. On going down in a group, the electrons get added in the next higher shell so, the attraction of the nucleus on the outermost shell decreases so, the size of the atom increases.
Some elements disobey general trends such as nitrogen or alkaline earth metals due to fully-filled and half-filled electronic configuration.