A chlorine atom has 17 protons and 18 neutrons in its nucleus. Therefore, its atomic number is ________ and the mass number is________

Explanation

To solve the question regarding the atomic structure of a chlorine atom with 17 protons and 18 neutrons, we can follow these steps:

### Step 1: Identify the Atomic Number
The atomic number (Z) of an element is defined as the number of protons in its nucleus.

- Given that the chlorine atom has **17 protons**, we can conclude that:
\[
\text{Atomic Number (Z)} = 17
...