Atomic number is defined in terms of protons and not in terms of electrons. Why?

Explanation

**Step-by-Step Solution:**

1. **Definition of Atomic Number**: The atomic number (Z) of an element is defined as the number of protons present in the nucleus of an atom of that element.

2. **Protons vs. Electrons**: In a neutral atom, the number of protons is equal to the number of electrons. However, when an atom becomes an ion (either a cation or an anion), the number of electrons changes while the number of protons remains constant.

3. **Formation of Ions**:
- A cation is formed when an atom loses one or more electrons. For example, if element X loses an electron, it becomes X⁺, but its atomic number (number of protons) remains the same.
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