Chem Exam 1 Flashcards
Quantum Numbers
tell us where to find electron in an atom (orbital and spin)
Principle Quantum Number
symbol: n
tells us the electrons energy level
the bigger the n value, the higher the energy level
Azimuthal Quantum Number
symbol (L)
Shape of the space where we might find electron
Magnetic Quantum #
symbol (ml)
Tells you orientation of orbital
when L = 0 there is only one possible orientation for
Spin Quantum #
(ms)
tells you the spin (up or down)
Electron Configuration
how electrons fill up the orbitals
Aufbau Principle
rule book for how electron configuration is filled
–> fill orbitals in order of increasing energy
Hund’s Rule
when filling up orbitals that have the same energy level, they will each occupy their own before doubling up
orbitals
0 = s
1 = p
2 = d
3 = f
Element Written
X = element
A = atomic mass #
Z = atomic #
Mass measured in
grams (g)
Volume measured in
liter (L) or cubic centimeter (cm3)
Amount measured in
atoms
molecules
moles
Temperature
Celcius (C)
Kelvin (K)
Energy is measured in
Joule (J)
calorie (cal)
Pressure
Pascal (Pa)
millimeters mercury (mm Hg)
atmosphere (atm)
torr, bar, psi
kilo (k)
1,000
centi (c)
0.01
mili (m)
0.001
micro (u)
0.000001 (5 zeros)
nano (n)
0.000000001 (8 zeros)
1 Kilometer =
1000 meters (1km = 1000m)
1 centimeter =
0.01 meters (1cm = 0.01 m)
1 millimeter =
0.001 meters (1mm = 0.001 m)
1 micro meter =
0.000001 meters (1um = 0.000001 m)
1 nano meter =
0.000000001 meters (1nm = 0.000000001 m)
Density =
mass/volume
cathode Ray Tibe Experiment
high voltage creates a stream of particles, they bent away from the negatively charged plate and towards the positively charged plate.
conclusion: existence of negatively charged particles (electrons)
Rutherords Gold Foil Experiment
fired particles at sheet of gold foil, some passed through others bounced back.
conclusion: the mass of the atom is concentrated in the positive nucleus around which electrons move
Discovery of neutron
James Chadwick
Isotopes
same element, different number of neutrons, isotopes can be identified by their mass
Mass Defect
amount of matter converted to energy when the nucleus of an atom is formed from protons + neutrons
wavelength (lamda- upside down y)
distance between identical points in a wave
frequency (v)
the number of peaks that pass through a point per unit of time
Constructive Interference
“in phase” waves come together to become a bigger wave
Destructive Interference
“out of phase” waves come together to cancel each other out
Plum pudding model
neutrons + protons –> the dough
electrons –> plum bits scattered throughout
Photoelectric effect + equation used
shinning light on a metal surface can cause e- to be ejected –> emitted e- are called photoelectrons
can measure photoelectron speed to determine their kinetic energy using =
KE electron = 1/2 (mass or electron)(velocity of electron)^2
Light behaves as…
A wave and has particle like characteristics
the minimum amount of energy required to detach an e- from a surface
KE electron = E photon - E0
0 = depends on metals identity
Bohr Model
only works for H- atom (simplest) not 100% correct, electrons do not orbit nucleus on set tracks
Heisenberg Uncertainty Principle
we cannot know both the position and speed of a particle, such as a photon or electron, with perfect accuracy; the more we nail down the particle’s position, the less we know about its speed and vice
Schrodinger
propose mechanical model
–> treats electrons as waves, e- behaves as waves each having a wave function
Schrodinger Equation
solution to the Schrodinger equation describes the 3D orbital shapes
Probability Density function
determine the probability of finding the e- in a given region around the nucleus
square of the wave function gives us probability of density
atomic orbital
region around the nucleus where the e- has 99% probability of being found
s orbital
3D spherical shape
p orbital
dumbbell shape
d orbital
cloverleaf shape
Pauli Exclusion Pirinciple
no two e- within an atom have the same set of four quantum numbers
