Matter It must have mass (weight) It must have volume (occupy space) Sunlight Gravity Rocks

Atomic Number Basic Chemistry Atom: Smallest part of an element. Can’t be broken down any further (maybe!). Nucleus - has protons (+ve) and neutrons (no charge) Orbitals - have electrons (-ve) # of protons = # of electrons. This makes the atom have no net charge (atom is neutral) Atomic Number = # of protons Ex. Atomic Number of Fe (Iron) is 26 Atomic Weight= # of protons + # of neutrons Ex: Atomic Weight of Fe (iron) is 26 + 30 = 56 Can you calculate number of neutrons if Atomic Weight and Atomic Number is known? # of Neutrons = Atomic Weight- Atomic Number Atomic Weight

6C12 Element is Carbon Atomic Number = 6 This means number of protons = 6 Also, number of electrons = 6 Mass Number = 12 = (Atomic Weight) Number of Neutrons = 12 - 6 = 6

Element: substance composed of one kind of atom & can not be broken down by normal chemical means.

Ion: an atom that has gained or lost electrons, giving it a positive or negative charge. Gold Ion has lost an Electron

Salt is Sodium Chloride Sodium (Na) atom Chlorine (Cl) atom SALT is NaCl Note: NaCl is a compound - has 2 elements

Isotope: a form of atom having the same atomic number but a different atomic weight Example 6C12 6C14 Radioactive Isotope Number of Neutrons will be different in ISOTOPES!

CHOPKINS CaFe Mg NaCl Chopkins café (has) mighty good Salt C = Carbon H = Hydrogen O = Oxygen P = Phosphorus K = Potassium I = Iodine N = Nitrogen S = Sulfur Ca = Calcium Fe = Iron Mg = Magnesium Na = Sodium Cl = Chlorine

Molecules and compounds A compound Combination of two or more elements Combined “chemically” Has definite proportions A molecule Smallest part of most compounds Hard to break up into element that make it C6H12O6 What is the difference between a compound and a molecule? A molecule is formed when two or more atoms join together chemically. A compound is a molecule that contains at least two different elements. All compounds are molecules but not all molecules are compounds. Molecular hydrogen (H2), molecular oxygen (O2) and molecular nitrogen (N2) are not compounds because each is composed of a single element. Water (H2O), carbon dioxide (CO2) and methane (CH4) are compounds because each is made from more than one element. The smallest bit of each of these substances would be referred to as a molecule. For example, a single molecule of molecular hydrogen is made from two atoms of hydrogen while a single molecule of water is made from two atoms of hydrogen and one atom of oxygen. O2

Molecules and compounds Match the following: NH3 Hydrogen Gas C55H72O5N4Mg Ammonia H2 Water C6H12O6 Chlorophyll A H2O Glucose Sugar