Sc, the first member of first transition series does not exhibit variable oxidation state. Why ?

Explanation

To answer the question of why Scandium (Sc), the first member of the first transition series, does not exhibit variable oxidation states, we can follow these steps:

### Step 1: Understand the Atomic Structure of Scandium
Scandium has an atomic number of 21. This means it has 21 electrons. The electronic configuration of Scandium can be written as:
- 1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹ 4s²

### Step 2: Identify the Valence Electrons
In the case of Scandium, the valence electrons are those in the outermost shell, which includes the 4s and 3d orbitals. The relevant electrons for Scandium are:
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