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Element Box page 7
Atomic number
14
Chemical Symbol
Si
Atomic mass
Name
28.086
Silicon
amu = atomic mass unit
 The mass of subatomic particles is so small
that a special unit of measurement is needed
just for them.
1 proton = 1 amu
1 neutron = 1 amu
1 electron = < 1amu
 Remember most of an atom’s mass is in the
nucleus: p + n
* see Gateway p15 : draw each example
Atomic number
 The number of
protons found in the
nucleus
 Each atom of an
element has a
specific number of
protons and
electrons so no two
elements are the
same.
Atomic Mass
 The number of
protons + the
number of
neutrons
 Most of an
element’s mass
is in the
nucleus.
Helpful Hints
Mass
- Atomic #
# Neutrons
Atomic # =
Protons =
Electrons =
all the same #