Column I contains definitions of some terms. Column Il contains the terms being defined. On the
line at the left of each definition in Column I, write the letter of the term being defined in Column II.
Column I
Column II
4.
5.
6. the average mass of the naturally occurring
isotopes of an element based on the mass of a
carbon-12 isotope whose mass is set at exactly 12
the number of protons in the nucleus of an atom
the number of protons in the nucleus of an atom
plus the number of neutrons
7.
the part of an atom where the protons and neutrons
are found
8.
9.
the region in an atom where an electron is found,
according to today's model of the atom
the nucleus of a helium atom
a. orbital
b.
C.
mass number
atomic number
d. nucleus
e.
atomic mass
f. alpha particle
