Transcript The atomic number tells how many protons Protons make an atom

The atomic number tells how
many protons
Protons make an atom what it is!
79 protons make gold. If I added
another proton it would actually
turn into Mercury!
The atomic number tells how
many protons
Protons are all the same. If I try
to put two together, they push
away from each other.
It seems that neutrons can act to
help glue protons together.
The atomic mass tells how
many protons AND neutrons
there are in the nucleus
The number of neutrons do NOT
make a difference in the
identity of an atom
Atoms of the same element will
ALWAYS have the same # of
protons, but MAY have different
neutrons
Atoms of the same element
with different atomic masses
are called isotopes
Gold has a mass of 196.97
That means MOST gold atoms have 197
p+ and no, but some rare atoms will have
only 196. They ALL have 79 p+. Most
have 118no, but a few may have 117 no.
In other words, there are two
isotopes of gold
Atomic mass = p+ + no
Atomic # = number of protons
If you want to know how many
neutrons
Atomic mass – atomic # = no
Now that we can determine the number
of protons, neutrons in the center of the
atom, let’s move to the outside of the
atom!
Electrons travel around the outside of
the nucleus in orbitals or shells!
Each shell can only hold a certain
number of electrons before they are
FULL! K = 2
L=8
M=8
N = 18
O = 18
P = 32
Q =32
Let’s draw a Calcium atom
40
Ca
20
20 p+
2 e-
8e-
2e-
20 no
8e-