Basic Chemistry The study of matter

Elements Simple substances composed of 1 type of atom Cannot be broken down by ordinary chemical means 96% of most organisms made of: C, H, N, O

Periodic Table

ATOMS Smallest part of an element that retains the element’s properties

Isotopes Atoms with same # protons, different # neutrons React the same way as “normal” atoms

Uses of Isotopes All isotopes have same chemical characteristics C-14 can be used in dating fossils Radioisotopes can be used to trace biochemical pathways DNA sequencing Medically – diagnostics and treatment

Radioactive Decay

Electron Energy Levels Electrons move around the nucleus of an atom in orbitals The further away from the nucleus an electron is, the more energy it has Valence electrons are the most energetic electrons

Compounds and Molecules Chemical compounds – atoms of 2 or more elements combined in fixed ratio Molecules – 2 or more atoms joined covalently

Formulas Molecular Formula – type & # of atoms C 6 H 12 O 6 Structural Formula – type, #, and arrangement of atoms

Chemical Equations Describe chemical reactions: Reactant  Products Some reactions are reversible Dynamic Equilibrium

Chemical Bonds Ionic Bonds Covalent Bonds Hydrogen Bonds edia/ch02/bond_types.html edia/ch02/bond_types.html

Redox Reactions Oxidation-reduction reactions Transfer of electrons from one substance to another Oxidation – process of losing electrons Reduction – process of gaining electron Oxidation and reduction always occur together

Redox Reactions