What will be the composition of the nucleus of the atom of an element with atomic number 19 and mass number 39?

Explanation

To determine the composition of the nucleus of an atom with an atomic number of 19 and a mass number of 39, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definitions**:
- The **atomic number** (Z) of an element is the number of protons in its nucleus.
- The **mass number** (A) is the total number of protons and neutrons in the nucleus.

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