Basic Chemistry of Life

Basic Chemistry of Life

AP Biology:Ch. 2-Chemical Context 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 ElementsC, 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 Structure3 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

http://drbein.net/chemistry.htmhttp://itc.gsw.edu/faculty/spea

vy/spclass/chemistry/atoms.htm

Traditional View 3D View of Orbitals

Animation of Atomic Structure (NOVA Podcast)

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)

C6

12.01

Atomic Number

Atomic Mass

How many protons and

neutrons does a carbon atom

have?

Changes to Atoms

Add/subtract protons--change element completely

Carbon (6 protons)-1 proton

Boron (5 protons)

Changes to AtomsAdd/subtract neutrons--change atomic mass, change stability of atom, creates isotopes (same element, different weight)

carbon 12 (atomic

weight of 12)

carbon 14 (atomic

weight of 14) -2 neutrons

Changes to AtomsAdd/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 AtomsAtoms 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 AssignmentPick 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!