What are atoms that have gained or lost electrons?
a. ions
b. isotopes
c. elements
d. molecules

They are called... ions.
Ions have negative charges. They also contain more protons than electrons.
I hope this helps!

If a hydrogen atom is neutral, it must also have  one electron. an oxygen atom (o) has an atomic number of eight (8). this means a neutral oxygen atom has eight protons and eight electrons. the element actium (ac) has an atomic number of 89, so it has 89 protons and 89 electrons in a neutral atom