4.2

Question 1

a subatomic particle that has a positive charge and that is found in the nucleus of an atom

Answer 1

proton

Question 2

a unit of mass that describes the mass of an atom or molecule

Answer 2

atomic mass unit

Question 3

the number of protons in the nucleus of an atom; the atomic number is the same for all atoms of an element

Answer 3

atomic number

Question 4

an atom that has the same number of protons as other atoms of the same element do but that has a different number of neutrons

Answer 4

isotope

Question 5

a subatomic particle that has no charge and that is found in the nucleus of an atom

Answer 5

neutron

Question 6

the sum of the numbers of protons and neutrons in the nucleus of an atom

Answer 6

mass number

Question 7

the mass of an atom expressed in atomic mass units

Answer 7

atomic mass

Question 8

pulls objects toward one another

Answer 8

gravitational force

Question 9

holds the electrons around the nucleus

Answer 9

electromagnetic force

Question 10

helps protons stay together in the nucleus

Answer 10

strong force

Question 11

an important force in radioactive atoms

Answer 11

weak force