130 likes | 330 Views
Basic Chemistry of Life. AP Biology: Ch. 2-Chemical Context of Life. Basic Components. Atom --The smallest unit of matter that retains basic properties of an element Element --A substance that cannot be broken down into other substances; contains all of the same type of atoms
E N D
Basic Chemistry of Life • AP Biology: • Ch. 2-Chemical Context of Life
Basic Components • Atom--The smallest unit of matter that retains basic properties of an element • Element--A substance that cannot be broken down into other substances; contains all of the same type of atoms • Compound--A substance consisting of two or more elements
Important Elements • C, H, N, O, P, S--Most common elements, very important for life • Ca,K,Na, Cl, Mg--also very important • Trace elements--needed in small amounts for important chemical reactions(ex. Fe, Zn)
Atomic Structure • 3 subatomic particles • Proton--positive charge (in nucleus) • Neutron--neutral charge(in nucleus) • Electron--negative charge(in orbitals) • An orbital is a region where an electron is mathematically predicted to be (probability field); More electrons, more complex the orbitals
Atomic Structure 3D View of Orbitals Traditional View http://itc.gsw.edu/faculty/speavy/spclass/chemistry/atoms.htm http://drbein.net/chemistry.htm
Basic Properties • Atomic Number--Number of protons; this defines the element. • Atomic Mass--SUm of protons and neutrons; Electrons almost have no weight so has little effect on total atomic mass.
Carbon (An Example) How many protons and neutrons does a carbon atom have? Atomic Number C 6 12.01 Atomic Mass
Changes to Atoms • Add/subtract protons--change element completely Carbon (6 protons) Boron (5 protons) -1 proton
Changes to Atoms • Add/subtract neutrons--change atomic mass, change stability of atom, creates isotopes (same element, different weight) carbon 14 (atomic weight of 14) carbon 12 (atomic weight of 12) -2 neutrons
Changes to Atoms • Add/subtract electrons--change overall charge of atom, change reactivity of atom, creates ions Na (11 electrons), Cl (19 electrons) Transfer 1 electron Na+ (10 electrons), Cl- (20 electrons)
Basic Rules for Atoms • Atoms always want to be stable • Radiation occurs when atoms release protons and neutrons to become stable, releasing excess energy in process (isotopes). • Will react with other atoms to become stable; create or destroy bonds, free radicals (ions)
Your Assignment • Pick one element and identify its atomic number and atomic mass • Then identify common isotopes and ions that occur for that element. Note the specific differences (ex. exact change in atomic weight) • Post your findings as comments to this VoiceThread. First come, first serve--no repeats...the sooner you act the more elements you can chose from!