The entire mass and positive charge of an atom is concentrated into its............

Answer

To solve the question, "The entire mass and positive charge of an atom is concentrated into its............", we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of an Atom**:
- An atom consists of three main subatomic particles: protons, neutrons, and electrons.
- Protons carry a positive charge, neutrons are neutral, and electrons carry a negative charge.

2. **Identifying the Location of Mass and Charge**:
- The mass of an atom is primarily due to protons and neutrons, as they are significantly heavier than electrons.
- The positive charge of an atom is due to the presence of protons.

3. **Locating the Nucleus**:
- According to atomic theory, particularly Bohr's model, protons and neutrons are located in the nucleus of the atom.
- Electrons revolve around the nucleus in defined energy levels or shells.

4. **Conclusion**:
- Since the entire mass of the atom (from protons and neutrons) and its positive charge (from protons) are concentrated in the nucleus, we conclude that the answer to the question is "nucleus".

### Final Answer:
The entire mass and positive charge of an atom is concentrated into its **nucleus**.

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