Quantum mechanical model Flashcards
orbits vs. orbitals
Orbits :
Bohr model
Two dimensional
Distance from nucleus is fixed
Path is elliptical or circular
Orbitals: density plots showing rpobability of finding an electron
Quantum model
Three dimensional (x,y,z planes)
Distance from nucleus varies
No set path
quantum mechanics
application of quantum theory to explain the properties of matter, particularly electrons in atoms
wave function
the mathematical probability of finding an electron in a certain region of space
electron probability density
probability of finding an electron at a given location, derived from wave equations and used to determine the shapes of orbitals also called an electron probability distribution
quantum numbers
describe the quantum mechanical properties of orbitals; from the solutions of Schrodinger’s wave equations
- required to describe any distinct electrical charge of the electron creates in its own magnetic feild
- there are 4 quantum numbers
principal quantum number
- shells
- the quantum number that describes size and energy of an atomic orbital, whole number values, the higher the shell number the further it is from the nucleus
- (n) #1-7
the secondary quantum number
- subshells
- describes shape, a positive number from 0– n-1
-(l)
0=s
1=p
2=d
3=f
the magnetic quantum number
- (ml)
- describes orientation of an atomic orbital in space relative to other orbitals in the atom
- has to be whole number values equal or less then l
- can only be -l or +l
the magnetic spin quantum number
- relates to the spin of the electron
- limitied to either +1/2 or -1/2
- since only 2 e- are able to fit in any one orbital, the e- accquire a positive (upright) or negative (downward) spin
- electrons behave as tiny magnets, they spin about its axis, the revolving electrical charge of the electron creates its own magnetic feild
formula for total # of orbitals for any energy level
n^2
the formula for the greatest # of electrons possible for any energy level
2n^2
the afbau principle
electrons enter lowest avalible energy level first
pauli’s exclusion principle
- no 2 e- in the same atom can have the sane 4 quantum numbers
- 2 electrons can go in each orbital, providing they have opposite spins
hund’s rule of maximum multiplicity
- when in orbitals of equal energy, electrons will try to remain unpaired
- all in row must have one e- before another is added
exceptions to the 3 electron configuration laws
cu, ag, au- all fill in 3d orbital before 4s to create more stable, also explains why cu can be cu+ and cu2+
- cr and mo, to acheive a more stable arrangement of lower energy, one of the 43 electrons is promoted into the 3d oribital to give 6 unpaired electrons with lower repulsion (w does not do this due to sheidlijg affect from f orbital)
more stable meaning
maximizes attractive forces and minimizes repulsive forces
why is iron magnetic
- the more unpaired e-, the more magnetic
- iron exhibits magnetic properties because it has 4 unpaired e- in its d orbota; that all have the same directionbal spin and all act as small magnets
- multiple iron atoms that have the same unpaired e- orientated in the same direction generate stronger magnetic feild
how is the periodic table arranged
according to the way electrons arrange themselves around the nuclei of atoms
