1. Section 1.3
The Periodic Table

2. Periodic Table Introduction
The arrangement of the elements show how chemical properties can be related
The arrangement shows the relationship between electronic structure and chemical properties
The elements are arranged in order of increasing atomic number reading from left to right and from the top to the bottom

3. Groups A group (AKA family) is a vertical column
Each group has the same number of valence electrons
This gives the group similar chemical properties
The groups are numbered from 1 to 18

4. More About Groups
The group number is the same as the number of valence electrons for the neutral atom in that group for the left side, and the group number minus 10 for the right side.
Example: carbon is in group 14 and has 4 valence electrons
Usually the noble gases are thought of as having 8 valence electrons, i.e. their outermost energy level is full

6. Periods A period is a row in the periodic table
Periods are numbered 1-7
Each period corresponds to a new main energy level
The first element in each period has only one electron in its outer shell
The second-to-last element in the period only requires one more electron to fill the outer shell

7. More About Periods
The last element in a period has all its electron shells filled and are known as the noble gases
The noble gases experience very little chemical reactivity

8. Periodicity
Periodicity is the regular repeating of properties according to the arrangement of elements in the periodic table
Chemical and physical properties of elements show periodicity if the elements are arranged in order of increasing atomic numbers

9. Metals
Metal: an element that is a good conductor of heat and electricity
Most metals are solids at room temperature
Most have the property of malleability (can be hammered or rolled into thin sheets)
Most are ductile (can be drawn into a wire)
Metals have high tensile strength (the ability to resist breaking when pulled)

10. More About Metals Most metals have luster (tend to be shiny)
Metals can also have diverse properties
Mercury is a liquid at room temperature
Group one metals are very soft while others are hard
Some are brittle while others are very malleable

11. Metals

12. Nonmetals
A nonmetal is an element that is a poor conductor of heat and electricity
Many are gases at room temperature
One nonmetal, bromine, is a liquid
Solid nonmetals include C, P, Se, S, and I. They tend to be brittle.

13. Nonmetals

15. Metalloids
A metalloid is an element that has some characteristics of metals and some characteristics of nonmetals
All are solids at room temperature
Less malleable than metals, but not as brittle at nonmetals
Tend to be semiconductors
Used in computers, digital watches, TV, and radios

16. Metalloids

18. Noble Gases Noble gases are the elements in group 18 Very unreactive
All are gases at room temperature
Ne, Ar, Kr, and Xe are used in lighting
He is used in party balloons and weather balloons

20. Two Other Sets of Elements
Two sets of elements are placed below the periodic table
They are called the lanthanides and the actinides
They are metallic, and fit into the table just after elements 57 and 89.
They are placed below the table to keep the table from being too wide.