Which is the most fundamental property of an atom

Explanation

**Step-by-Step Solution:**

1. **Understanding Atomic Structure**: An atom consists of a nucleus, which contains protons and neutrons, surrounded by electrons. The protons in the nucleus carry a positive charge.

2. **Definition of Atomic Number**: The atomic number of an element is defined as the number of protons present in the nucleus of an atom. It is denoted by the symbol 'Z'.

3. **Significance of Atomic Number**: The atomic number is crucial because it uniquely identifies an element. Each element has a distinct atomic number, which determines its position in the periodic table and its chemical properties.

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