1. Nonmetals and Metalloids

2. What is a nonmetal?
Elements that lack most of the properties of metals.
Located to the right of the zigzag line in the periodic table.
Very common elements
Extremely important to all living things on Earth

3. Physical Properties Many are gases at room temperature
Opposite to those that characterize the metals
Dull
Break apart or easily crumble into pieces.
Poor conductors of heat and electricity

4. Chemical Properties
Readily form compounds; however, group 18 rarely ever do

5. Compounds of Nonmetals
When nonmetals and metals react – valence electrons move from the metal atom to the nonmetal atom.
Na + Cl = NaCl
Nonmetals can form compounds with other nonmetals too.
Atoms share electrons
Many even form molecules of two identical atoms – diatomic molecules (O₂ , N₂, H₂)

6. Families of Nonmetals Carbon Family Nitrogen Family Oxygen Family
Halogen Family
Noble Gases
Hydrogen

7. Carbon Family Group 14 Each element has atoms with 4 valence electrons
Only one element is a nonmetal – Carbon
Two are metalloids – silicon and germanium
Two are metals – tin and lead

8. Nitrogen Family Group 15 Contain 5 valence electrons
Two nonmetals – nitrogen and phosphorus

9. Oxygen Family Group 16 Six valence electrons
Three nonmetals – oxygen, sulfur, selenium
The oxygen we read is a diatomic molecule
Ozone is a triatomic molecule
Oxygen is very reactive and can combine with almost any element.

10. Halogen Family
Group 17
Fluorine, chlorine, bromine, iodine and astatine
All are nonmetals except astatine
7 valence electrons
All are very reactive, most are dangerous to humans

11. Noble Gases
Group 18
Do not ordinarily form compounds with other elements
Do not gain, lose or share their valence electrons
Generally very stable and unreactive
All exist in Earth’s atmosphere in small amounts

12. Hydrogen
Hydrogen has chemical properties very different from other elements in family.
Makes up more that 90% of the atoms in the universe
1% of mass of Earth’s crust, oceans, and atmosphere
Rarely found on Earth as a pure element

13. Metalloids
Have some of the characteristics of metals and some of nonmetals
Seven metalloids
Most common is silicon
Most useful property is their varying ability to conduct electricity.
Some are used to make semiconductors