SCIENCE REVIEWER

democritus

proposed that matter is composed of indivisible particles

john dalton

billiard ball model - atom is a uniform, solid sphere

j.j. thompson

discovered electrons, made the plum pudding model

ernest rutherford

conducted gold foil experiment, discovered that protons circulate around the electron

niels bohr

made the planetary model where electrons move in circular orbits within specific energy levels

erwin schrodinger

made the electron cloud model

james chadwick

discovered neutrons

dmitri mendeleev

made the periodic table

periodic table

shows all knowns elements, organized by chemical properties

electron configuration

the way electrons are distributed in the different orbitals around the nucleus of an atom

aufbau principle

electrons occupy orbitals in order of increasing energy

pauli’s exclusion principle

only two electrons can fit into a single orbital and must be an opposite spin

orbital diagrams

pictorial descriptions of the electrons in an atom

hund’s rule

electrons go into different orbitals in the same sub-level before pairing up inside

quantum number

used when describing the energy levels available to atoms

principal quantum number (n)

the size of the orbital

angular quantum number (l)

the shape of the orbital

magnetic quantum number (ml)

the orientation in space of a particular orbital

electron spin quantum number (ms)

the direction of the spin of an electron

possible values of principal

1,2,3,4,5,6,7

values of angular

s = 0, p=1, d=2, f=3

values of magnetic

s=0, p=-1,0,+1, d=-2,-1,0,+1+2 f=-3,-2,-1,0,+1,+2,+3

values of spin

+1/2, -1/2

ionic bond

metal+nonmetal, “transfer” of electron

covalent bond

nonmetal+metal, “share” of electron

metallic bond

metal+metal

ions

atoms that carry positive or negative charge.

cations

positive charge, lose lectrons

anions

negative charge, gain electrons

NaCl

rock salt crystals

SiO2

amethyst

HgS

cinnabar

greater than or equal to 0.4

nonpolar

0.5 - 1.9

polar

greater than 2.0

ionic