The first ionisation energies of the elements of the transition series.

Options

A. increases as the atomic number increase.
B. decrease as the atomic number increase.
C. do not show any change as the addition of electrons takes place in the inner `(n-1)` d-orbitals.
D. increase from `Ti` to `Mn` and then decrease from `Mn` to `Cu`.

Answer

A

Explanation

First ionisation energies of `3d`-series (first transition series) increase with increase in atomic number due to `(A)` increase in nuclear charge `(B)` decrease in atomic size.