CHEM Electron Configuration
Pauli Exclusion Principle
maximum of two electrons may occupy an atomic orbital, but only if they have opposite spins
Full Configuration for Mg
1s²2s²2p⁶3s²
Electron Configuration for Si
1s²2s²2p⁶3s²3p²
Electron Configuration for Ar
1s²2s²2p⁶3s²3p⁶
Electron Configuration for Kr
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶
Electron Configuration for Sr
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²
Full Configuration for Rh
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶5s²4d⁷
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p²
Ge
1s¹
H
1s²
He
Wavelength
Horizontal distance between two consecutive crests or troughs in a wave
Frequency
How many waves can pass a given point per second.
1s²2s²2p³
N
energy levels
what do the coefficients stand for? (1s²)
sublevels (or orbitals)
what do the letter symbols stand for? (1s²)
PAULI EXCLUSION PRINCIPLE
* 2 arrows in same box have to point in opposite ways * 2 electrons in same orbital have to spin in opposite ways
ORBITAL
* Always hold up to 2 electrons * Little boxes in orbital notation
HUNDS RULE
* Fill in each box once, then start filling in the second one * Bus rule
EXCITED STATE
* Higher energy (think of when did the flame test lab and the element changed color)
AUFBAU PRINCIPLE
* Last set of boxes might not be full... fill in order
GROUND STATE
* Lowest electron energy
SHORTHAND NOTATION
* Put the closest noble gas symbol in parenthesis * Continue electron configuration where it leaves off after noble gas
SUBLEVEL
* S sublevel- up to 2 electrons (I box) * P sublevels- up to 6 electrons (3 box) * D sublevels- hold up to 10 electrons (5 box) * F sublevels- hold up to 14 electrons (7 box) * Tell of the shape of the orbitals in each energy level
ORBITAL NOTATION
* Show electron configurations in more detail * Electrons in their orbitals * Each box represents one orbital and shows how many electrons (up to 2) are in that orbital * Little boxes under the sublevel
ENERGY LEVEL
* Where electrons are found * (2-8-8) * Big numbers represent the energy levels
# of orbitals in any s sublevel
1
# of orbitals in any p sublevel
3
p orbitals
3 mutually perpendicular dumbbell shaped orbitals; second to fill from 2nd energy level on up; can hold max of 6 electrons
# of orbitals in any d sublevel
5
d orbitals
5 orbitals of cloverleaf shape; third to fill for any energy level; beginning in the third shell, contains a total of 10 electrons; higher in energy than s and p orbitals in the same shell.
# of orbitals in any f sublevel
7
Photon
A quantum, or discrete amount, of light energy.
Atomic emission spectrum
A set of frequencies of electromagnetic waves given off by atoms of an element; consisting of a series of fine lines of individual colors.
Ground state
A state in which all the electrons in an atom have the lowest possible energies
Orbital
A three-dimensional region around the nucleus that indicates the probable location of an electron
1s²2s²2p⁶3s²3p¹
Al
1s²2s²2p⁶3s²3p⁶
Ar
Electron configuration
Arrangement of electrons in the orbitals of an atom.
Spectrum
Array of electromagnetic radiation displayed in order of wavelength
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p³
As
1s²2s²2p¹
B
1s²2s²
Be
Why do we fill the 4s orbital before the 3d orbital?
Because the 4s is lower in energy than the 3d, so it is filled first.
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁵
Br
1s²2s²2p²
C
1s²2s²2p⁶3s²3p⁶4s²
Ca
1s²2s²2p⁶3s²3p⁵
Cl
1s²2s²2p⁶3s²3p⁶4s²3d⁷
Co
1s²2s²2p⁶3s²3p⁶4s¹3d⁵
Cr
1s²2s²2p⁶3s²3p⁶4s¹3d¹⁰
Cu
Aufbau principle**
Electrons fill an atom in order of increasing energy level, starting at the lowest level.
1s²2s²2p⁵
F
1s²2s²2p⁶3s²3p⁶4s²3d⁶
Fe
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p¹
Ga
what happens to an electron when it absorbs energy?
Jumps to excited state
1s²2s²2p⁶3s²3p⁶4s¹
K
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁶
Kr
1s²2s¹
Li
1s²2s²2p⁶3s²
Mg
1s²2s²2p⁶3s²3p⁶4s²3d⁵
Mn
1s²2s²2p⁶3s¹
Na
1s²2s²2p⁶
Ne
1s²2s²2p⁶3s²3p⁶4s²3d⁸
Ni
Pauli's exclusion principle**
No more than two electrons of opposite spin can occupy a given orbital.
1s²2s²2p⁴
O
Hund's rule**
Orbitals of equal energy are each occupied by one electron before any orbital is occupied by a second electron, and all electrons in singly occupied orbitals must have the same spin
1s²2s²2p⁶3s²3p³
P
1s²2s²2p⁶3s²3p⁴
S
1s²2s²2p⁶3s²3p⁶4s²3d¹
Sc
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰4p⁴
Se
1s²2s²2p⁶3s²3p²
Si
quanta
Small specific amounts of energy; The amount of energy needed for an electron to jump from one energy level to the next
Quantum
The amount of energy needed to move an electron from one energy level to another
1s²2s²2p⁶3s²3p⁶4s²3d²
Ti
1s²2s²2p⁶3s²3p⁶4s²3d³
V
1s²2s²2p⁶3s²3p⁶4s²3d¹⁰
Zn
Electromagnetic radiation
a form of energy that exhibits wavelike behavior as it travels through space
photons
a quantum of light; a discrete bundle of electromagnetic energy that interacts with matter similarly to particles
electron cloud
a region around the nucleus of an atom where electrons are likely to be found (most probable location)
Energy level
a region of set energy around the nucleus where electrons are likely to be found moving.
excited state
an electron in a temporarily higher energy level than in its ground state
valence electrons
an electron in the highest occupied energy level of an atom;available to be lost, gained, or shared in the formation of chemical compounds
How do you determine the # of Valence electrons?
by counting the # of s and p electrons since the most recent noble gas
Hund's Rule
electrons occupy equal energy orbitals so as to maximize the number of unpaired electrons
what happens to an electron when it releases energy?
falls to ground state
Erwin Schroedinger
he gave rise to the Quantum Mechanical Model with his calculation of the probability of where an electron can be found around the atom
Nitrogen
name the element 1s²2s²2p³
Aluminum
name the element 1s²2s²2p⁶3s²3p¹
Titanium
name the element [Ar]4s²3d²
Tungsten
name the element [Xe]6s²4f¹⁴5d⁴
orbitals
regions within electron cloud where electrons orbit the nucleus; number of orbitals differs with sublevel type (s,p,d,f)
sublevels
regions within the energy levels; corresponds to the block grouping s,p,d,f on the Periodic Table
s orbitals
spherical orbitals; first to fill for any energy level; can only hold 2 electrons
Aufbau Principle
states that each electron occupies the lowest energy orbital available
electron configuration
the arrangement of electrons in the energy levels, sublevels and orbitals of atoms
Hertz (Hz)
the unit of frequency, equal to one cycle per second
f orbitals
their shapes are even more complex than s, p, or d orbitals; can hold a total of 14 electrons in 7 sub-shells; in the fourth and fifth energy levels
shorthand notation
uses noble gas configuration from the preceding full level (stable core), along with electrons on current level
The number of electrons in a sublevel
what to the superscripts stand for? (1s²)
ground state
when all the electrons in an atom have the lowest possible energies
