In an atom with atomic no. 39 and mass no. 89,the number of electron is:

Options

A. 89
B. 39
C. 50
D. 45

Explanation

To find the number of electrons in an atom with atomic number 39 and mass number 89, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Atomic Number**: The atomic number of the atom is given as 39. The atomic number (Z) represents the number of protons in the nucleus of the atom.

2. **Understand the Relationship Between Protons and Electrons**: In a neutral atom, the number of electrons is equal to the number of protons. This means that if we know the atomic number, we can directly determine the number of electrons.

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