Periodic Table
Unit IV
I History
A. Mendeleev
• Arranged elements by their masses
B. Moseley
• Arranged elements by their atomic number
• Modern periodic table
II Arrangement of the Periodic Table
A. Groups
 Columns on the table
 18 Groups
 Contain the same number of valence electrons
B. Periods
 Rows on the table
 7 Periods
 Use the same energy levels
III Types of Elements
A. Metals
1. Location
a) Lower left side of the table
2. Properties
a) Metals are malleable and ductile
b) Metals are solids at room temperature except mercury
c) Metals have luster
d) Metals are good conductors
e) Metals have low ionization energy and low electronegativity
f) Metals lose electrons and form positive ions
B. Nonmetals
1. Location
a) Upper right side of the table
2. Properties
a) Nonmetals are brittle
b) Nonmetals are gases or molecular solids at room temperature
except bromine which is a liquid
c) Nonmetals are dull
d) Nonmetals are insulators
e) Nonmetals have high ionization energy and high
electronegativity
f) Nonmetals gain electrons and form negative ions
C. Metalloids
1. Location
a) On the “stairs” plus Ge and Sb
2. Properties
a) Metalloids are brittle
b) Metalloids are solid at room temperature
c) Metalloids have luster
d) Metalloids are semi-conductors
e) Metalloids have middle ionization energy and electronegativity
values
f) Metalloids gain or lose electrons
D. Transition Metals
1. Location
a) Groups 3 through 12
2. Properties
a) Transition metals have multiple oxidation states
b) Transition metals form colored ions
E. Noble Gases
1. Location
a) Noble Gases are in Group 18
2. Properties
a) Noble gases are inert which means they do not react
b) Noble gases are monatomic
c) Noble gases have filled outer energy levels
• 8 valence electrons (or 2)
IV Properties of Elements
A. Atomic Radius
• ½ distance between two nuclei
B. Ionic Radius
• Metals decrease in size
• Nonmetals increase in size
C. Reactivity
• Metal activity increases as you go left and down
• Nonmetallic activity increases as you go up and to the right
V Groups
A. Alkali Metals
• Group 1
• Explosive in water
B. Alkaline Earth Metals
• Group 2
C. Halogens
• Group 17
•
•
All nonmetals
All phases of matter
• F2 and Cl2 (gas)
• Br2 (liquid)
• I2 (solid)
D. Noble Gases
• Group 18
• Do not react except the largest members
VI Trends
As you go down a group
• Atomic number increases
• Mass increases
• Valence electrons remain the same
• Energy levels increase
• Metallic character increases
• Nonmetallic character decreases
• Radius increases
• IE and EN decrease
As you go across a period
• Atomic number increases
• Mass increases
• Valence electrons increase
• Energy level is constant
• Metallic character decreases
• Nonmetallic character increases
• Radius decreases
• IE and EN increase