Question

A neutral atom of fluorine has a mass number of $19$ and an atomic number of $9$. How many neutrons does it have?

• A. $10$
• B. $9$
• C. $19$
• D. $28$
• E. It is impossible to determine from the information given.

Answer 1

The correct option is A $10$

Mass number, $A=19$

Atomic number, $Z=9$

Number of neutrons=$A-Z=19-9=10$