An atom with an atomic number of 33 is ionized and found to have a charge of -3. How many electrons in the atom? What is the isotope symbol of this atom ?*

Explanation:

The element with atomic number of 33 is Arsenic (As)

ionized and found to have a charge of -3.

The negative sign denotes that it gained an electron. So -3 means it gained 3 electrons.

How many electrons in the atom?

Total number of electrons = Number of electrons gained + Electrons in it's neutral state

Total electrons = 3 + 33 = 36

What is the isotope symbol of this atom ?

As³⁻ it has the same number of electrons with Krypton (Kr)