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3.00_Chemistry of Biology
Biology I
Periodic Table of the Elements
Slides 33-44
1
Organizing Elements (Patterns)
The Periodic Table of Elements is a way of
organizing the elements in relation to each
other so it is easy to find elements that have
similar properties.
2
Periodic Table of the Elements
How do you read the PERIODIC TABLE?
3
Mass Number
4
Periods
Each row is called a “period”
The elements in each period have the same number
of electron shells
Hint:
A period comes at the end of
a sentence--a horizontal
line.
5
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Periods (Rows) Properties
Seven periods on a periodic table
(numbered from the top down)
Atomic numbers and atomic
masses increase as you move from
the left to the right in a period
All atoms of the elements in the
same period have the same number
of orbitals/levels
All atoms of the elements in a
specific period have that
respective number of
orbitals/levels
6
Periods
The horizontal rows of the periodic table are
called periods.
Elements in a period are not alike in properties.
The first element in a period is usually an
active solid, and the last element in a period is
always an inactive gas.
7
Periods
Rows
Atomic size (number of protons) decreases
from left to right across a period.
Atomic mass (number of protons) increases
from left to right across a period.
8
Periods
Rows
Metals are on the left
Non-metals are on the right
9
Groups or Families
Group 1 = 1 electron
Group 2 = 2 electrons
Group 8 = 8 electrons
Except for He, it has 2
electrons
Each column is called a
“group” or family.
Each element in a group
has the same number of
electrons in its outer
orbital, also known as
its outer shell.
The electrons in the
outer shell are called
“valence electrons.”
Hint: Your Family tree is vertical.
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10
Groups or Families
• The vertical (up and down)
columns of the periodic table
(there are 18) are called groups
or families.
• Elements in the same group or
family have similar
characteristics or properties.
11
Groups Names
Group 1: Alkali metals
Group 2: Alkaline earth metals
Group 3-11 : Transition Metals
Group 11: Coinage metals/Copper
Family
Group 12-14: Metalloids &
nonmetals
Group 15: Pnictogens /Nitrogen
Family
Group 16: Chalcogens /Oxygen
Family
Group 17: Halogens /Halide
Family
Group 18: Noble gases
12
Periodic Table of the Elements
13