Weeks 1-5 Flashcards
Avogadro’s number (constant)
Na =6.022 *10^23 mol-1
Mole
6.022 140 76 *10^23 entities
Describe the quantum numbers n, l, and ml and use them to determine valid electron configurations for atoms
aufbau principle
electrons occupy the lowest energy orbitals first
Hund’s rule
most stable arangement of electrons within an orbital has the greatest number of parallel spins
plancks constant
6.626*10^-24 Js n (h)
de broglie wavelength =
h/(mv)
n= principal quantum number
determines energy and orbital radius
(orbital energy)
l= orbital
determines orbital shape and angular momentum (sub-shell) values 0 to n-1
m l = magnetic qunatum no
determines the orientation of an orbital
ms
specifies spin of the electron in the orbital
values +1/2 -1/2
the larger n is
the greater average distance
l determines shape and name of orbital
l=0 s orbital
l=1 p orbital
l=2 d orbital
l=3 f orbital
m determines number of each type of orbital
for 1=0 there is one S orbital (sphere no orientation) the m1=0
for 1=1 there are 3p m1=-1,0,1
for 1=2 there are 5d orbitals m1= -2-1,0,1,2
for
why does the orbital energy lchange so much from 1s to to 2p and 2s
s-orbitals can penetrate furhter toward the nucleus than p-orbitals (greater penetration power) and therefore feel greater attration to the nucleus
as a result 2p energy is higher than 2s
atomic number
the amount of protons
shells with larger n have more sub-shells
because the number of subshells depends on n
two factors that affect the energy of an electron in the outermost orbital.
1.) the nuclear charge- adding protons lowers orbital energy
due to attractive forces between protons and outer electrons
2.) the presence of other electrons on the atom
adding core electrons increases orbital energy
due to increased shielding of the outer electrons from the nucleus
addition of electrons in the same shell increases orbital energy
due to repulsive forces between electrons in the same region in space
Physical separation
separates gas molecules on the basis of their size or mass
Chemical separation:
separates gas molecules based on the strength of their interactions with each other or another type of material or through reaction
Le chateliers principle
When an external change is made to a system in a dynamic equilibrium, the system responds to minimise the effect of the change
open system
can exchange mass and energy (usually as heat) with its surroundings.
Example: an open water bottle.
closed system
allows the transfer of energy (as heat) but not mass. Example: a stoppered water bottle.
isolated system
does not allow the transfer of either mass or energy. Example: a closed thermos flask.
