Nonmetals, Inert Gases, and Semimetals Chapter 4, Section 4 Nonmetals, Inert Gases, and Semimetals

Properties of Nonmetals Nonmetal = an element that lacks most of the properties of a metal Poor conductors of electric current and heat Solid nonmetals are dull and brittle (not malleable or ductile) Many are common elements of Earth sulfur Table Talk: What are some of the properties of a metal?

Physical Properties 4 nonmetals are gases at room temperature: Nitrogen (N) Oxygen (O) Fluorine (F) Chlorine (Cl) Most nonmetals are solids Only one is a liquid Bromine (Br) phosphorus Chlorine gas

Chemical Properties + = Atoms on nonmetals usually gain or share electrons when they react with other atoms When metals react with nonmetals, electrons move from the metal atoms to the nonmetal atoms Example: sodium + chlorine = NaCl (table salt)

Table Talk: Summarize some physical and chemical properties of non metals. NO PEEKING!

Uses of Some Common Nonmetals Carbon (C): In all living things Coal, crude oil & gasoline (fuel) Nitrogen (N): Earth’s atmosphere is 90% Nitrogen gas Bacteria in soil use nitrogen compounds & create fertilizers for plants Phosphorus (P): Very reactive & ignites easily; used in match tips

Oxygen (O): Sulfur (S): Oxygen (O2) is a gas in the air that is required for respiration ozone (O3) is also in our upper atmosphere and helps screen the sun’s harmful rays. (At ground level it is a dangerous pollutant) Sulfur (S): Smells like rotten eggs Used to make tires and other rubber products Also used to make sulfuric acid (H2SO4), an important chemical in industry

Chlorine (Cl): used to kill bacteria and make table salt (NaCl) Flourine: small amounts of flouride are added to water to help prevent cavities

Table talk: name some common uses of non-metals

Inert Gases Also known as the noble gases Elements in Group 18 Tend to be unreactive (do not usually gain, lose, or share electrons) All exist in Earth’s atmosphere in small amounts Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), and Radon (Rn)

Hydrogen is Unique! Element with the simplest atoms (one proton/one electron) Not in a group because its chemical properties are so different from all other elements Makes up more than 90% of the atoms in the universe, but only 1% of Earth’s crust, oceans, and atmosphere Rarely found on Earth in it’s pure form; usually found as H2O

Table Talk: Explain to a partner what makes hydrogen so special.

Semimetals Between the metals and nonmetals in the periodic table Some properties of metals, some of nonmetals Most common is silicon (Si) Silicon Dioxide (SiO2) is sand, which is the main component of glass The most useful property is their varying ability to conduct electricity (semiconductors) – used in transistors, computer chips and lasers end