Daltons Model (disproven)
- elements made indivisible, indestructible particles called atoms
- all atoms of element are identical & have same properties
Daltons Model (true)
- atoms of different elements combine forming compounds
- compounds contain atoms in small whole number ratios
- atoms can combine in more than than one way to form different compounds
Thompsons Model
dense positive charge w/ negative charge electrons interspersed
Rutherfords Gold foil experiment
alpha particles were directed at a thin sheet. most passed few deflected -> atomic nucleus
a) if plum pudding model correct, alpha particles would pass without deflection
b) since small number deflected -> idea most of mass and all +charge of atom concentrated in space smaller than nucleus size
atomic number
(Z) number of protons (also # electrons if a neutral atom)
Mass number
(A) total # of protons & neutrons in nucleus of atom
similarities b/t protons electrons
protons and electrons same -> atom neutral
isotopes
- atoms of same element with different number of neutrons
- have same atomic number
amu
atomic mass number
electromagnetic radiation
type of energy travels thru space at 3.0 x 10^8 m/s exhibits wave and particle like behavior.
e.g. light
wavelength (lamba)
distance between adjacent wave crests
frequency (v)
of cycles or crests that pass thru stationary point in one sec.
white light
continuous spectrum
light
visible radiant energy
visible spectrum
region of light spectrum our eyes can see
radiant energy spectrum (EM spectrum)
continuous spectrum of visible and invisible light that ranges from short to long lamba.
wave length *
- increases to the left
- longer wavelength = lower frequency
wavelength and frequency
inversely related
wavelength and energy
inversely related
frequency and energy
directly related
x rays
ionizing radiation
ultraviolet (UV) and infrared (IR) light
invisible to human eye
microwaves
absorbed by water molecules and used to heat water containing substances
ROYGBIV
red. orange. yellow. green. blue. indigo. violet.
photon
packet of light energy
quantum concept
energy is composed of discrete units (its quantized)
energy level
electrons travel in fixed energy orbits
bohr atom
electrons exits in specific distances from nucleus and occupy orbits of discrete energy levels
emission light spectrum
associated with emission of electromagnetic radiation by elements or compounds; collection of narrow bands of light energy
quantum numbers
energy of each bohr orbit has specific numbers (n=1,2,3…)
quantized
fixed
ground state
lowest energy state
excited state
when an electron is in a higher energy orbital
subshell
(energy sublevel) s (sphere), p(dumbbell), d (clover leaf), and f (no specific shape)
8A
noble gases
electron configuration
shows occupation of orbitals by electrons for particular atoms that is
subatomic particles
positive (+) negative (-) neutron
2 types of atomic notation
^3H & H-3
calculating protons neutrons and electrons
- neutrons = mass number - atomic number
- protons = atomic number
- identify element by # of protons
bohr model of atom
- energy levels (n=1,2,3…)
- energy levels correspond to periodic table
- energy levels are aka principal quantum numbers
energy levels get closer the further away are from nucleus
electromagnetic radiation lab
- continuous spectrum (white light) produces rainbow
- color of each discharge tube
- 1 electron relaxing = 1 photon emitted
