It matters. MATTER: ELEMENTS AND COMPOUNDS It matters.

Anything that has a mass and a volume

Close up view of atoms and their behavior Animated images are from

Changing from one state to another is a physical change If a new substance is formed it is a chemical change Images are from

The building blocks of Matter consist of Protons (+), Electrons (-), and Neutrons (N) Images are from

Consist of only one kind of atom Cannot be broken down into a simpler type of matter by either physical or chemical means without losing their identity Can exist as either atoms or molecules

In the Earth’s crust, Oxygen is the most abundant element (46.6%) Silicon is the second most abundant element (27.7%) Aluminum (8.1%), Iron (5.0%), Calcium (3.6%), Sodium (2.8%), Potassium (2.6%), and Magnesium (2.1%) complete the list of elements that account for about 98.5% of the total mass of the earth’s crust

Aluminum, Iron, Oxygen, and Silicon make up about 88 percent of the earth's solid surface Water on earth’s surface and in the air as clouds and fog are made of Hydrogen and Oxygen The air is 99 percent Nitrogen and Oxygen Hydrogen, Oxygen, and Carbon make up 97 percent of a person Almost everything you see in this picture is made up of just six elements: Hydrogen, Oxygen, Carbon, Nitrogen, Aluminum, and Silicon

Animated images and notes from Atoms of two or more different elements chemically bound together  Ex: H 2 O, NaCl, C 6 H 12 O 6, CO 2 Can be broken down into elements again through a chemical reaction In the animation above, water (H 2 O) is a compound made of Hydrogen and Oxygen.

The properties of the elements that make up a compound are often quite different from the properties of the compound itself Sodium (Na) is a highly reactive metal Chlorine (Cl) is a poisonous gas Sodium Chloride (NaCl) is table salt

Compounds are made of molecules A molecule is 2 or more atoms chemically bonded Water = 2 atoms of Hydrogen and one atom of Oxygen = H 2 O A molecule is the smallest particle of a compound that has all the properties of that compound As all atoms of a certain element are alike, so are molecules of a certain compound alike

In the animation above, two nitrogen atoms (N + N = N 2 ) make one Nitrogen molecule.

A shorthand way of representing compounds If chemical symbols are the letters, these are the words Ex: NH 3 = ammonia C 3 H 7 OH = rubbing alcohol Sometimes the formula represents a molecule of a single element These are called diatomic molecules and this is how that element is naturally found O 2 = Oxygen H 2 = Hydrogen Cl 2 = Chlorine

Subscripts are small numbers used in chemical formulas They are placed to the lower right of the chemical symbol Subscripts represent # of atoms of an element in the compound CO 2 = 1 atom of Carbon and 2 atoms of Oxygen H 2 SO 4 = 2 atoms of Hydrogen, 1 atom of Sulfur and 4 atoms of Oxygen

Elements are pure substances that make up all matter on earth The smallest piece of an element is an atom Compounds are things made of a combination of elements The smallest piece of a compound is a molecule Atoms combine to form molecules