Question

1. An isotope is an atom of an element that differs in its number of _______________.

A. protons
B. neutrons
C. eletrons


2. What determines what element an atom is?

A. the number of protons and neutron in an atom
B. the number of electrons in the atom
C. the number of neutrons in the atom
D. the number of protons in the atom


3. Which of the following contributes to the mass number?

A. Number of protons and neutrons
B. Number of protons only
C. Number of neutrons and electrons
D. Number of protons and electrons

Answer 1

1. B; An isotope is an atom of an element that differs in its number of neutrons.

2. A; the number of protons and neutrons determines what element an atom is.

3. A; the number of protons and neutrons contributes to the mass number of an element.