NOTES – 4.3: Atomic Number, Mass Number, Isotopes and Atomic Mass
Summary of atomic structure (sketch diagram):
ATOMIC NUMBER:
● Designates the in a nucleus of an atom
● Each element has a (the same
atomic # for ALL atoms of the same element)
● The number of electrons
MASS NUMBER:
● Designates the
● Number of neutrons =
● Atoms of the same element can have
Periodic Table Symbol Key:
Determining # p+, n, and e- from chemical symbols:
● Example 1:
# protons =
# electrons =
# neutrons = =
● Example 2:
# protons =
# electrons =
# neutrons = =
6
C
Carbon
12.011
_____________ (Z)
_____________
_____________
_____________ (A)
# of protons = Z
# of electrons = (in a neutral atom)
# of neutrons =
14
C
6
15
N
7
Mass #
Atomic #
