SAT Subject Physics Practice Question 639: Answer and Explanation
5. A negative ion is an object that has
A. more electrons than neutrons.
B. more electrons than protons.
C. more protons that neutrons.
D. more protons than electrons.
E. more neutrons than electrons or protons.
Correct Answer: B
The correct answer is (B). A negative ion is an object that has an excess of electrons. Electrons are the negatively charged part of the atom, therefore they give an object that carries excess of electrons a negative charge.