chem unit 5 Flashcards
(35 cards)
wavelength
The shortest distance between equivalent points on continuous waves.
usually expressed in meters,centimeters, or nanometer
Frequency
the number of waves that pass a given point per second
speed
the rate of distance per unit time.
- all electromagnetic radiation travels at the same speed (3.00 x108)
amplitude
the height of a wave from the origin to the crest or from the origin to the trough
biggest wavelenght to smallest
radio waves, microwaves, infrared, visible light, ultra-violet, X-rays, gamma rays
which has the highest frequency
gamma rays
equation 1
speed of light = wavelength multiply by velocity
plank’s constant
6.626 x10-34 J.s
Incandescence
making an object so hot it emits light
- different wavelength of light emitted at different temp
- light only be emitted with E are multiple of Hv
Photoelectric effect
Electrons are ejected from a metal surface when light of a certain frequency shines on it.
Photons
a particle of electromagnetic radiation that carries a quantum of energy
atomic emission spectra
is the set of frequencies of that electromagnetic waves emitted by atoms of that element
- only certain colors are observed, which mean only certain frequencies are emitted
- elements absorb at the same frequencies they emit
Niels Bohr Fix
- electrons only in allowed orbits
-orbits prevent electrons from spiraling into the nucleus
-orbits can be calculated mathematically
-labeled energy levels (orbits) with quantium number (n)
ground state
the lowest energy level or N=1
what does the Bohr model explain
- explains the location of electrons
-explained how elements behave chemically
-explained the atomic spectrum of hydrogen or any 1e- species
problem with Bohr model
-only explains the emission spectrum for hydrogen
- does not accurately describe the location of the electron
-conflict with Heisenberg uncertainty principle
Heisenberg uncertainty principle
from the photoelectric effect, photons can eject an electron
-trying to see an electron disturbs it
- fundamentally impossible to know both position and velocity of the electrons
energy levels
electrons have certain energy levels, N where N=1,2,3 etc
- for each energy level (n) there are n2 total orbitals
Quantum mechanical model of the atom
- Erwin Shrodinger developed an equation to treat the electron as a wave
- works for hydrogen (simplifies to the bohr equation) and works for all other atoms
-the model treating electrons as waves is the Quantum Mechanical Model of the atom
electron density
can’t say exactly where the electron is, so use Electron density
Definition- probability that the e- is at a point in space
high electron density
likely the electron is there
low density
unlikely the electron is there
how many orbitals does sublevel S have?
1
how many orbitals does sublevel p have
3
