Which of the following pairs are isoelectronic ?
`K^(+),Sc^(3+)`

Explanation

To determine whether the pairs \( K^{+} \) and \( Sc^{3+} \) are isoelectronic, we need to follow these steps:

### Step 1: Identify the atomic numbers
- **Potassium (K)** has an atomic number of 19.
- **Scandium (Sc)** has an atomic number of 21.

### Step 2: Determine the number of electrons in each ion
- For \( K^{+} \):
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