Periodic Table
•Periodic means a regular, repeating
pattern.
•Atomic mass is the average mass of one
atom of the element.
Periodic Table Notes
Groups (family)=columns (18), elements
that have similar characteristics.
e.g. Group 1 has metals that react
violently with water!
Group 18 are the noble gases
and rarely react with anything!
Periodic Table Notes
Periods=rows (7), movement from left to
right shows a gradual change in
properties.
e.g. From highly reactive (on the
left) to least reactive (on the right).
Bohr Model of the Atom
Nucleus=(center circle) contains
protons and neutrons.
Electron shells=(outer circles)
contains electrons.
Bohr Model of the Atom
Only a set amount of electrons
can go in each shell. The shell
must (in most cases) be filled in
order before moving to the next
level.
Bohr Model of the Atom
1st level K: 2
2nd level L: 8
3rd level M: 18
4th level N: 32…
Periodic Table Information:
27
Co
Cobalt
58.933
The atomic number
The chemical symbol
The element name
The atomic mass
Periodic Table Information:
27
Co
Cobalt
58.933
The atomic number
The atomic number is equal to the
number of protons (P).
The number of protons is equal to the
number of electrons (E).
Periodic Table Information:
27
Co
Cobalt
58.933
The atomic number
The atomic mass is equal to the number of
protons (P) + the number of neutrons (N).
To find the number of neutrons:
subtract the atomic number from the
atomic mass! (Always round the
atomic mass to the nearest whole
number).
Cobalt: P=27
E=27
N=32
AM-AN=
59-27=32
Periodic Table Information:
27
Co
Cobalt
58.933
Protons have a (+) charge
Electrons have a (-) charge
Neutrons have no charge
Time to practice!