Quantum theory and electronic structure (part 2) Flashcards
The shell number
defines the location of the energy level.
Another name for shell
principal quantum number (n)
Another word for sub shell
angular momentum quantum number (l)
sub shell
tells us the shape of the orbitals
for a given number of n, l has a possible value of 0 to n-1
radial distribution function
a plot of the probability of finding an electron in each shell against the distance from the the nucleus
Magnetic quantum number (m)
describes the orientation of an orbital in space and therefore the number of each orbital in each sub shell
m has an integer value
if l = 0 then m = 0
if l = 1 then m = -1 0 1
f l = 2 then m = -2 -1 0 1 2
Spin quantum number
indicates the spin of the electron. There are two possibilities, spin up (ms = +1/2), and spin down (ms = -1/2)
Wolfgang Pauli
in a given atom no two electrons can have the same set of quantum numbers (n, l, ml, ms).
Since electrons in the same orbital have the same values of n, l, ml, it means that they must have a different value of ms. however since there are only two possible values for ms. There can only be 2 electrons in an orbital.
Principal quantum number
identifies the main energy level
Angular momentum number (summary)
indicates the shape of the orbital
Magnetic quantum number (summary)
specifies orientation in space (number of orbitals)
electron spin quantum number
indicates the direction of electron spin
The four quantum numbers
act as an eircode for the electron.
The Paulis exclusion principle states that no more than two electrons in an atom can have the same four sets of quantum numbers.
if they have the same four quantum numbers they could occupy the same location in space at the same time
Aufbau principle
electrons occupy the lowest energy levels first
General energy ordering for electrons
Electrons fill the lowest energy levels first in order to minimise the mercy of the atom
Orbitals cannot hold more than 2 electrons each with opposite spins
When orbitals of identical energy are available, electrons occupy them singly before occupying them in pairs.
Hund’s rule
Electrons are distributed in subshells of orbitals of identical energy in such a way as to give the maximum numerical of unpaired electrons ‘bus seat rule’
Valence electrons
electrons in the outermost principal quantum level of an atom (n=1, n=2 etc)
valency electrons are electrons involved in bonding
group 1 = valency 1
group 2 = valency 2
group 3 = valency 3
group 4 = valency 4
group 5 = valency 5
group 6 = valency 6
group 7 = valency 7
group 8 = valency 8
Predicting ionic charges
using electron configurations
predict whether it would be easier for an element to lose or gain an electron which will then predict its charge
eg if an element has 7 electrons in its outermost shell it will be easier for to to gain an electron than lose 7
Nobel gases has a full outermost shell and are the most stable all other elements aim to have a configuration like that of a Nobel gas
groups and charges
group 1 = +1 charge when they react with non-metals
group 2 = +2 charge when they react with non-metals
group 7 = form diatomic molecules (very reactive)
group 8 = form monoatomic molecules (very unreactive)
periodic table
going across = group
going down = period