Final answer:
An atom with an unequal number of protons and electrons is called an ion. It can be positively charged (cation) or negatively charged (anion), depending on whether it has lost or gained electrons.
Step-by-step explanation:
An atom that is unbalanced between proton and electron count is called an ion. Atoms are typically electrically neutral, containing the same number of positively charged protons and negatively charged electrons. When these numbers are not equal, the atom has an overall charge, either positive or negative.
If an atom has more protons than electrons, it forms a positive ion known as a cation. Conversely, if an atom has more electrons than protons, it forms a negative ion known as an anion. This process is referred to as ionization, which can occur due to high levels of radiation or electron transfers with other atoms.
Ions are highly reactive due to their charge imbalance and can attract or repulse other charged particles. Additionally, they are affected by magnetic fields because of their electrical charge.