Isotopes are those atoms which have same ………..

Explanation

**Step-by-Step Solution:**

1. **Understanding Isotopes**: Isotopes are defined as atoms of the same element that have the same number of protons but different numbers of neutrons. This means that they share the same atomic number but have different mass numbers.

2. **Identifying Atomic Number**: The atomic number of an element is the number of protons in its nucleus. For isotopes, this number remains constant. For example, all carbon isotopes (C-12, C-13, C-14) have an atomic number of 6, indicating they each have 6 protons.

3. **Understanding Mass Number**: The mass number of an isotope is the total number of protons and neutrons in the nucleus. Since isotopes differ in the number of neutrons, they will have different mass numbers. For instance, C-12 has 6 neutrons, C-13 has 7 neutrons, and C-14 has 8 neutrons.

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