The atoms of the same element may differ in the number of ________.

Options

A. electrons only
B. protons only
C. neutrons only
D. both electrons and protons.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Question:**
The question asks what can differ in atoms of the same element. To answer this, we need to consider the fundamental particles that make up an atom: protons, neutrons, and electrons.

2. **Identifying Key Particles:**
- **Protons:** The number of protons in an atom defines the element. For example, all carbon atoms have 6 protons.
- **Electrons:** In a neutral atom, the number of electrons equals the number of protons. Therefore, the number of electrons cannot differ in atoms of the same element.
- **Neutrons:** The number of neutrons can vary in atoms of the same element, leading to the formation of isotopes.

3. **Defining Isotopes:**
Isotopes are variants of the same chemical element that have the same number of protons but different numbers of neutrons. For example, carbon has isotopes like Carbon-12 (6 protons and 6 neutrons) and Carbon-13 (6 protons and 7 neutrons).

4. **Calculating Neutron Numbers:**
- For Carbon-12 (6C12): Neutron number = Mass number - Proton number = 12 - 6 = 6 neutrons.
- For Carbon-13 (6C13): Neutron number = Mass number - Proton number = 13 - 6 = 7 neutrons.

5. **Conclusion:**
Since the number of neutrons can vary while the number of protons remains constant for a given element, we conclude that the atoms of the same element may differ in the number of **neutrons**.

**Final Answer:**
The atoms of the same element may differ in the number of **neutrons**.

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