6 Families (groups) – vertical columns Elements in a family have similar propertiesPeriods – rows, left to right add another proton and electron – filling up outer energy (valence) level
7 Elements are Made of Atoms The single smallest unit of an element that retains all of the chemical and physical properties of its parent element is called an atom.Atoms are made up of smaller, subatomic pieces called protons, neutrons and electronsHelium
8 Atoms are composed of three types of subatomic particles Electrons: have a negative charge and are the smallest part of an atomProtons: have a positive charge and mass of 1amuNeutrons: have no charge1 neutron = 1 amuProtons and neutrons clump to make the nucleusThe electrons surround the nucleus and form the much larger electron cloud.
9 Atomic Number Atomic number defined as the number of protons Because atoms are neutral: # electrons = # protonsAtoms of the same element always have the same atomic number2311
10 Chemical BondsAtoms are not stable unless their valence (outermost) energy level is filled.By forming bonds with other atoms, valence levels are filled.Barium
11 Two types of bondsAtoms may fill their valence levels one of two ways:share electrons with other atoms to form a covalent bondorAtoms can gain or lose electrons to create an ionic bond
12 Ionic Bonds (Salts)Formed when electrons are transferred between atoms – one loses and the other gainsAtom that has gained or lost an electron is now charged and called an ionAtom that loses electrons becomes + and the one that gains is -
13 Covalent BondsElectrons are shared: single pair shared = single covalent bond, 2 pairs shared = double covalent bond
14 Chemical FormulasTell kinds and numbers of atoms in one molecule (or smallest unit) of a substanceSubscripts tell the number of atoms of the element to the upper left (of the subscript).Eg. H2OTells us there are 2 atoms of H and 1 of O in one molecule of water (if no subscript, then it is understood to be 1)
15 CO21 carbon dioxide molecule has 1 carbon atom bonded to 2 oxygen atoms.
16 Chemical EquationsRepresent chemical reactions, which obey the law of conservation of matter – the kinds and numbers of atoms that enter into the reaction also come out!Coefficients tell how many of the molecules they precede are involved.Eg. 2Mg + O MgORead as magnesium plus oxygen yields magnesium oxideSubstances to the left of the arrow are reactants, and substances to the right are productsIn this reaction, 2 atoms of magnesium react with 2 atoms of oxygen to produce 2 molecules of magnesium oxide.
18 pH refers to the concentration of H+ or OH- ions Lower pH – higher concentration of H+ and the greater the acidityHigher pH – higher concentration of OH- and the greater the alkalinity (base)Organisms – and tissues within organisms have specific pH requirements.
19 Inorganic Molecules Simple Structure H20, 02, NH3, CO2 Inorganic even though it contains carbon - exception
25 PolymerizationSmaller units (monomers) are bonded together to make larger units (polymers)A disaccharide such as maltose or sucrose is made from the dehydration synthesis (condensation reaction or removal of H2O) of 2 monosaccharidesIf more than 2 monosaccharides are bonded through dehydration, a polysaccharide (starch) is made. Cellulose is an example
26 PROTEINS Composed of monomers called amino acids Contain C, H, O, sulfur and nitrogen!Structure and chemicals that affect other body processes: enzymes, hormones