4.2 Flashcards
1
Q
atomic number
A
the number of protons in the nucleus of an atom
2
Q
isotope
A
atoms that have the same number of protons but have different numbers of neutrons
3
Q
mass number
A
the sum of the number of protons and neutrons in the nucleus of an atom
4
Q
atomic mass
A
the mass of an atom expressed in atomic mass units
