52. Select a statement which describes mass defect.
a. The mass of the nucleus of an atom after a period of radioactive
b. The difference between the mass of the nucleus and the mass of its
53. State the definition of half life.
The time re-
54. Select the three types of changes that take place in matter.
quired for half
of the number
a. Chemical, natural, and artificial.
b. Chemical, physical, and artificial.
c. Physical, chemical, and nuclear.
d. Chemical, nuclear, and radioactive.