Patterns in the Periodic Table
In a row…
Period
• A row on the periodic table is called a period.
A period…
1
2
3
4
5
6
7
Orbitals…
Period
• A row on the periodic table is called a period.
• The number of the period indicates how many
electron orbitals there are in each atom.
Osmium…
6
Maximum electrons…
Period
• A row on the periodic table is called a period.
• The number of the period indicates how many
electron orbitals there are in each atom.
• The number of elements in a period also
indicates the number of electrons that can fit
in that orbital
A period…
1
2
Period 2
1 has 8
2 elements
The second
first orbital
orbital
cancan
hold 2
8 electrons
A group
• Look at your Bohr models for Nitrogen and
Phosphorus, Oxygen and Sulphur, and Flourine
and Chlorine, see anything interesting?
• In a group, such as group 1, the outermost
orbital has the same number of electrons in
each element
Group 1
1p+
1e-
11p+
12n0
2e- 8e- 1e-
Hydrogen
Sodium
3p+
4n0
Lithium
2e- 1e-
19p+
20n0
2e- 8e- 8e- 1e-
Potassium
A group
• In a group, such as group 1, the outermost
orbital has the same number of electrons in
each element
• Because electrons are the outermost particles
in an atom, they are the ones that give an
atom it’s properties, so elements with similar
outer orbitals, have similar properties
Groups
Group 1: Alkali Metals
Very Reactive, react violently
with water
Groups
Group 17: Halogens
Very reactive nonmetals
Groups
Group 18: Noble (Inert) Gasses
Unreactive gaseous elements
Two Major Divisions of Elements
This line is the division between
METALS and NONMETALS
Why does the periodic table have an
extra section?
To save space!
To save space!