Question

1. choose the best answer. an element that gains or loses an electron is a(n) __. ion positron isotope valence element 18. choose the best answer. an element that has a different number of neutrons than protons is a(n) __. ion isotope positron valence element

Explanation:

1. An ion is an atom or molecule that has gained or lost one or more electrons, resulting in a net electric charge.
2. An isotope is an atom of an element that has a different number of neutrons than protons, giving it a different atomic mass. A positron is the antiparticle of the electron, and a valence - element is not a standard scientific term in this context.

Answer:

1. ion
2. isotope