Chemistry – study of matter and the changes it undergoes

Only 1 kind of atom 2 or more different kinds of atoms

Element is a pure substance made up of only one kind of atom.

Families (groups) – vertical columns Elements in a family have similar properties Periods – rows, left to right add another proton and electron – filling up outer energy (valence) level

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 electrons Helium

Atoms are composed of three types of subatomic particles Electrons: have a negative charge and are the smallest part of an atom Protons: have a positive charge and mass of 1amu Neutrons: have no charge 1 neutron = 1 amu Protons and neutrons clump to make the nucleus The electrons surround the nucleus and form the much larger electron cloud.

Atomic Number Atomic number defined as the number of protons Because atoms are neutral: # electrons = # protons Atoms of the same element always have the same atomic number 2 3 11

Chemical Bonds Atoms are not stable unless their valence (outermost) energy level is filled. By forming bonds with other atoms, valence levels are filled. Barium

Two types of bonds Atoms may fill their valence levels one of two ways: share electrons with other atoms to form a covalent bond or Atoms can gain or lose electrons to create an ionic bond

Ionic Bonds (Salts) Formed when electrons are transferred between atoms – one loses and the other gains Atom that has gained or lost an electron is now charged and called an ion Atom that loses electrons becomes + and the one that gains is -

Covalent Bonds Electrons are shared: single pair shared = single covalent bond, 2 pairs shared = double covalent bond

Chemical Formulas Tell kinds and numbers of atoms in one molecule (or smallest unit) of a substance Subscripts tell the number of atoms of the element to the upper left (of the subscript). Eg. H2O Tells 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)

CO2 1 carbon dioxide molecule has 1 carbon atom bonded to 2 oxygen atoms.

Chemical Equations Represent 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 + O2 2MgO Read as magnesium plus oxygen yields magnesium oxide Substances to the left of the arrow are reactants, and substances to the right are products In this reaction, 2 atoms of magnesium react with 2 atoms of oxygen to produce 2 molecules of magnesium oxide.

pH refers to the concentration of H+ or OH- ions Lower pH – higher concentration of H+ and the greater the acidity Higher pH – higher concentration of OH- and the greater the alkalinity (base) Organisms – and tissues within organisms have specific pH requirements.

Inorganic Molecules Simple Structure H20, 02, NH3, CO2 Inorganic even though it contains carbon - exception

Biological Macromolecules Organic (contain carbon) (polymer) Building Blocks (monomers) Function Sources Protein Amino acids Structure, enzymes, hormones Eggs, fish, chicken, meat, nuts, legumes, dairy Carbohydrates polysaccharides (starch – cellulose) Monosaccharides Simple sugars (glucose) Energy Fruit, veggies, bread, potatoes, pasta, grains Lipids (fats and oils) Fatty acids and Glycerol (Not monomers) Energy, structure, hormones Vegetable oils (olive, safflower), animal fats (butter) Nucleic acids DNA & RNA Nucleotides Carry genetic code and direct protein synthesis Cells

CARBOHYDRATES Sugars, Starches, Cellulose Contain C,H,O in a ratio of 1:2:1 Ratio of H:O is 2:1 just like H2O Eg. C6H12O6 Energy & energy storage

cellulose starch sugar

Glucose A monosaccharide C6H12O6, major source of energy in the body.

Monosaccharide + monosaccharide disaccharide

Polymerization Smaller 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 monosaccharides If more than 2 monosaccharides are bonded through dehydration, a polysaccharide (starch) is made. Cellulose is an example

PROTEINS Composed of monomers called amino acids Contain C, H, O, sulfur and nitrogen! Structure and chemicals that affect other body processes: enzymes, hormones

Peptide bond A dipeptide results

Amino Acids

There are 20 different types of amino acids found in the natural world.

LIPIDS Fats, oils and waxes Contain C,H,O with a very high ratio of carbon and hydrogen to oxygen. Composed of fatty acids and glycerol Uses: Cell membrane structure Energy Some Hormones Insulation

Lipids Include all of the fats, oils and waxes Lipids Include all of the fats, oils and waxes. They have higher ratios of Carbon & Hydrogen than oxygen.

Saturated vs Unsaturated Fats unsaturated has double bonds

Nucleic Acids DNA & RNA: carry genetic code Made of repeating units called nucleotides: Sugar + phosphate + N base Contain P

nucleotide