Neutron is present in all atoms except

Options

A. Nucleus
B. Deuterium
C. Tritium
D. Helium

Explanation

**Step-by-Step Solution:**

1. **Understanding Neutrons**: Neutrons are subatomic particles found in the nucleus of an atom. They have no electric charge (neutral) and contribute to the mass of the atom.

2. **Identifying Atoms Without Neutrons**: While most atoms contain neutrons, there is an exception. The simplest atom, which is Hydrogen (specifically the isotope known as Protium), does not have any neutrons. Protium has one proton and no neutrons.

3. **Conclusion**: Therefore, the only atom that does not contain neutrons is the isotope of Hydrogen known as Protium.

**Final Answer**: Neutrons are present in all atoms except in Hydrogen (specifically the isotope Protium).

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