The first series of transition metals refers to elements from Scandium (Sc) to Zinc (Zn), while the second series includes elements from Yttrium (Y) to Cadmium (Cd), and the third series starts with Lanthanum (La) and ends with Mercury (Hg).
Here are the comparisons of the electronic configurations for the respective vertical columns:
1. **First series (Sc-Zn):**
- The electronic configurations typically follow the pattern [Ar] 3d^(n) 4s^2, where 'n' represents the number of electrons in the d orbital. For example, Scandium (Sc) has the configuration [Ar] 3d^(1) 4s^2, and Zinc (Zn) has [Ar] 3d^(10) 4s^2.
2. **Second series (Y-Cd):**
- Similar to the first series, the second series follows the pattern [Kr] 4d^(n-1) 5s^2. For instance, Yttrium (Y) has the configuration [Kr] 4d^(1) 5s^2, and Cadmium (Cd) has [Kr] 4d^(10) 5s^2.
3. **Third series (La-Hg):**
- The third series follows the pattern [Xe] 4f^(n-1) 5d^(1) 6s^2. However, the filling of the 4f orbitals starts with Lanthanum (La), leading to anomalies in the electronic configurations. For instance, Lanthanum has the configuration [Xe] 5d^1 6s^2 instead of [Xe] 4f^(1-14) 5d^1 6s^2.
In summary, while the first and second series follow a straightforward pattern in their electronic configurations, the third series introduces complexity due to the filling of the 4f orbitals, leading to variations in the expected configurations.
