Question

The atomic number of an element Y is 17. The number of electrons in its ion Y⁻ will be ______.

Options

• 17

• 18

• 19

• 20

Answer 1

The atomic number of an element Y is 17. The number of electrons in its ion Y⁻ will be 18.

Explanation:

An atomic number of 17 means the neutral atom has 17 electrons. The single negative charge on the (Y⁻) ion indicates that the atom has gained one extra electron. Adding this gained electron to the original 17 gives the ion a total of 18 electrons.