1. Nonmetals and Metalloids

2. What are Nonmetals?
Nonmetals are elements located on the right side of the periodic table
Nonmetals do not have any of the properties of metals
Examples of nonmetals include:
-- nitrogen
-- oxygen
-- carbon
-- chlorine
-- argon

3. Physical Properties of Nonmetals
Nonmetals share several common physical properties:
-- nonmetals are dull, not shiny
-- solid nonmetals are brittle, not malleable or ductile
-- if you hammer them, they will break or crumble
-- nonmetals usually have lower densities than metals
-- nonmetals are poor conductors of heat and electricity

4. Chemical Properties of Nonmetals
The chemical properties of nonmetals are determined by the group (# of valence electrons) of the nonmetal
MOST NONMETALS gain electrons (negative charge) when they form ions because their valences shells are close to full
When nonmetals form compounds:
-- with metals, valence electrons move from the metal to the nonmetal
-- with other nonmetals, electrons are shared equally
Nonmetals often exist in nature as diatomic compounds
-- such as oxygen gas, O2, or hydrogen gas, H2
-- (these are two atoms of the same element)

5. Nonmetal Families The groups (families) of nonmetals are:
-- The Carbon Family
-- The Nitrogen Family
-- The Oxygen Family
-- The Halogens
-- The Noble Gases
Hydrogen is a special non-metal on the left side of the periodic table and is not in any family
-- most of the atoms in the universe are of hydrogen
-- hydrogen is the only non-metal to lose electrons when forming compounds

6. The Carbon Family
The Carbon family contains all non-metal elements in group 14 (IV) of the periodic table
-- the only element in this group is carbon!
Carbon is important for several reasons
-- it has four valence electrons, so it can bond to up to four other atoms
-- all living things are made of carbon
-- compounds made out of carbon are called organic compounds

7. The Nitrogen Family
The Nitrogen family consists of all non-metal elements in group 15 (V) of the periodic table
-- the two non-metals in this group are nitrogen and phosphorus
These atoms have 5 valence electrons
Nitrogen is used in living things, and is the most abundant gas in our atmosphere
Phosphorus is unstable, so it is only found compounds
-- phosphorus is used to make matches and flares

8. The Oxygen Family
The Oxygen family consists of all non-metal elements in group 16 (VI) of the periodic table
-- these elements are oxygen, sulfur, and selenium
These elements all have 6 valence electrons
Oxygen is used as the gas we breathe to live
-- also, the ozone layer is made up of O3 molecules
-- it is the most abundant element in earth’s crust and the second-most abundant in our atmosphere
-- oxygen is very reactive
Sulfur is a yellow, rotten-egg smelling non-metal
-- it is used in medicines and plastics

9. The Halogens
The Halogens are all the non-metal elements in group 17 (VII) of the periodic table
-- includes fluorine, chlorine, bromine, iodine, and astatine
The halogens have 7 valence electrons and are extremely reactive, wanting to gain the 1 electron needed to complete the valence shell
Most halogens are gases that are dangerous to humans
Halogen compounds are quite useful:
-- fluorine is in non-stick cookware and toothpaste
-- chlorine is in many salts
-- iodine can be used to purify water

10. The Noble Gases
The Noble Gases consist of all elements on the far right (group 18 or VIII) of the periodic table
The Noble gases have full valence shells (either 2 electrons for helium or 8 electrons for all others) and therefore are not reactive
Noble gases are used in several ways:
-- neon is used in signs
-- helium is used in balloons
-- argon is the 3rd most abundant gas in our atmosphere

11. Metalloids There are seven elements classified as metalloids
-- boron, silicon, germanium, arsenic, antimony, tellurium, and astatine
These are located on the “staircase” between the metals and non-metals
Metalloids have some characteristics of metals and others of non-metals
The most important use of metalloids is as of “semiconductors”, substances who can change the amount of electricity that they conduct
-- based on heat, light, etc. . .
-- very useful in computer chips