Chater 3 Energy And Energy Changes Flashcards
(25 cards)
Quantum mechanics
Branch of physics that deals with the behavior of atomic particles
Electromagnetic radiation
A type of energy embodied as oscillating electric and magnetic vectors
Amplitude
A measure of maximum displacement from a baseline
Wavelength, λ
Distance between two adjacent peaks/troughs
Frequency, ν
A measure of the number of cycles that passes a stationary point in a given true period
Refraction
The bending of waves as it passes from one medium to another of different densities
Diffraction
The bending of lights as it passes through a small opening
Fraunhofer lines
Missing energies from sunlight energy is continuous
Blackbodies
Emit radiation based on temperature
Coal
Red 1000k
Orange 1500k
White 2000k
Quantum
The smallest, discrete quantity of a particle form of energy
Quantized
Restricted to certain values. Energy of the atom is quantized.
Equantum=hv
E:energy j/quantum
h: plancks constant- 6.626e-34
v: frequency
Photoelectric effect
1.presence of a threshold frequency. Vmin. Red light==>no electron ejected Low V Blue light==>electron ejected High V 2.absence of a lag time Bright blue light>same time for electron vs. dim blue light
Photon
A quantum of electromagnetic radiation
Ephoton=hV e- ejected, only if
Elight>Φ
Φ=hVmin
φ: work function-minimum energy needed
If light>Φ Elight=Φ + KEe-
Neil Bohr
- e- reside in particular orbitals know. As stationary states
- energy of an e- in a stationary state is related to the distance from the nucleus
- electrons can move from one stationary state to another by absorbing or releasing energy equal to the difference in energies of the stationary state
- the energy of a stationary is given by its “principal quantum number”(n)-2.18x10^-18
E=———————
n^2
Quantum mechanics
electrons have wave like properties
λ=h/mu
Particle property
wave property complementary
position——-velocity
▵x •m▵u≥h/4π Heisenberg uncertainty
∆x: uncertainty in position
m:mass in kg
∆u: uncertainty in velocity
Principal quantum number, n(shell)
a value that determines the size and energy of an orbital.
Angular momentum quantum numer, l(subshell)
a value that determines the shape of an orbital
l=0,1,2…n-1
l=0 s orbital
l=1 p orbital
l=2 d orbital
l=3 f orbital
Magnetic quantum number, ml
value that describes the spatial orientation of an orbital.
ml= -l…-1,0,+1…+l
n=1 n=2
l=0 l=0,1
ml=0 ml=-1,0,+1
1s 2s,2p
Degenerate
having the same energies
Electron spin quantum number, Ms
all electrons have an intrinsic spin
Ms=+1/2,-1/2
spin up, spin down
Aufbak Priniciple
electrons occupy the lowest energy orbital first build up
Pauli exclusion principle
in an atom, no 2 electrons can have same for quantum numbers. An orbital can only hold 2 electrons
Hunds Rule
when filling degenerate orbitals, fill them singly first, with parallel spins
