What is a particle with an unequal number of protons and electrons?
Given that the question is posted in the chemistry section, I think the answer to the question is CLEARLY....
Atoms are composed of a dense, massive nucleus containing charged particles,
Around the positively-charged nucleus, electrons, particles of NEGLIGIBLE mass, but unit NEGATIVE, electronic charge, whizz about. In the neutral atom, NECESSARILY there are equal number of protons, massive, charged nuclear particles, and electrons, mass-less, extra-nuclear particles of OPPOSITE charge to the nuclear charge.
Now the identity of the element is defined by the number of nuclear charges...i.e.
Metal are reducing, electron-rich materials, and typically LOSE electrons to form cations:
On the other hand, non-metals are oxidizing, electron-poor materials, and typically GAIN electrons to form anions: