1. 12.3 The Periodic Table

2. The Periodic Table
- The periodic table organizes the elements according to how they combine with other elements (chemical properties).
- The periodic table is organized in order of increasing atomic number.

3. The Periodic Table
group: columns
period:
rows

4. Groups of the Periodic Table
Alkali metals
INCLUDES:
hydrogen
lithium
sodium
potassium
- highly reactive
- soft and silvery in pure form

5. Groups of the Periodic Table
Alkaline earth metals
INCLUDES:
beryllium
magnesium
calcium
- bond easily with oxygen:

6. Groups of the Periodic Table
Halogens
INCLUDES:
fluorine
chlorine
bromine
iodine
- tend to be toxic gases or liquids
- form salts with alkali metals:

7. Groups of the Periodic Table
Noble gases
INCLUDES:
helium
neon
argon
- do not naturally form chemical bonds with other atoms because of full electron energy levels
- almost always found in their pure state

8. Transition Metals
- usually good conductors of heat and electricity

9. Phases of the Elements Phases at room temperature: - most are solids
- 2 are liquids (blue above)
- 11 are gases (green above)

10. Metals, Nonmetals, Metalloids
Metalloids: have properties of both metals and nonmetals
Nonmetals: good insulators, brittle
Metals:
good thermal and electrical conductors, malleable, ductile

11. Periodic Properties of Elements
Periodicity means properties repeat each period (row) of the periodic table.

12. Atomic Mass - The mass of individual atoms is extremely small
- To make calculations easier, scientists use the atomic mass unit (amu).
- One atomic mass unit is about the mass of a single proton or neutron (1.66 x grams)
The atomic mass of any element is the average mass (in amu) of an atom of each element.