Question

question 17
what does it change in an ion?
the number of electrons
the number of neutrons
the mass numbers
the number of protons

Explanation:

An ion is formed when an atom gains or loses electrons. The number of protons determines the element's identity and doesn't change in ion - formation. Neutrons are not involved in the process of ion - formation for simple cases. Mass number is the sum of protons and neutrons and remains the same during normal ion - formation. The change occurs in the number of electrons, resulting in a charged particle.

Answer:

The number of electrons