The statement below is followed by four options. Each option is related to the item in the statement, but only one is always true. Select the option that always holds and makes the statement true.
"An ion always has ______."
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → An electric charge
The answer must hold for every ion, without exception. An option that is present in most cases but can be missing in even one case is not always true.
Option (1) A positive charge — the chloride ion (Cl−) has a negative charge.
Option (2) More than one atom — the sodium ion (Na+) is a single atom that has lost one electron.
Option (3) An electric charge — an ion is an atom or group of atoms that has gained or lost electrons, so it always carries a positive or a negative charge; a particle with no charge is not an ion, so this is always true.
Option (4) A metal atom — the chloride ion (Cl−) contains no metal.