BIOCHEMISTRY The chemistry of life

Levels of Organization Subatomic particlesAtomsMolecules Cell OrganellesCellsTissues OrgansOrgan SystemsOrganismsSpecies CommunitiesEcosystems BiosphereEarthSolar SystemGalaxyUniverse

Atoms The smallest functional unit of matter Contain Protons (+ charge), Neutrons (no charge), and electrons (-charge). The Protons AND neutrons reside in the nucleus and together make up the ATOMIC MASS . Just the protons (which are equal to the number of e-) make up the Atomic Number

6 Atomic Notation 12 C Atomic Mass Element Symbol Atomic Number In this case: The number of Protons is: 6 The number of electrons is: 6 The number of neutrons is: 6

Elements A substance that cannot be broken down into simpler substances Important ones you should know: C: carbon H: hydrogen O: oxygen Ca: calcium N: nitrogen S: sulphur Na: sodium K: potassium I: iodine Cl: chlorine Fe: iron Zn: zinc Mg: magnesium P: phosphorus

A Compound When two or more elements combine chemically Examples: H20, NaCl, FeO2 When elements form a compound, their characteristics change

Bonding Results in the formation of compounds Involves the transfer or sharing of electrons When atoms gain or lose electrons, they become electrically charged particles called ions, and an ionic bond is formed When atoms share electrons, a covalent bond is formed

Valence Shells The outer electron shell (orbital) in an atom determines its reactivity The innermost electron shell holds 2 electrons, all others hold 8

More Valence Shells O B F Ne P: 5 e-: 5 N: 6 11 5 19 16 8 9 20 10