Quantum theory and electronic structure (part 2)

Question 1

The shell number

Answer 1

defines the location of the energy level.

Question 2

Another name for shell

Answer 2

principal quantum number (n)

Question 3

Another word for sub shell

Answer 3

angular momentum quantum number (l)

Question 4

sub shell

Answer 4

tells us the shape of the orbitals
for a given number of n, l has a possible value of 0 to n-1

Question 5

radial distribution function

Answer 5

a plot of the probability of finding an electron in each shell against the distance from the the nucleus

Question 6

Magnetic quantum number (m)

Answer 6

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

Question 7

Spin quantum number

Answer 7

indicates the spin of the electron. There are two possibilities, spin up (ms = +1/2), and spin down (ms = -1/2)

Question 8

Wolfgang Pauli

Answer 8

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.

Question 9

Principal quantum number

Answer 9

identifies the main energy level

Question 10

Angular momentum number (summary)

Answer 10

indicates the shape of the orbital

Question 11

Magnetic quantum number (summary)

Answer 11

specifies orientation in space (number of orbitals)

Question 12

electron spin quantum number

Answer 12

indicates the direction of electron spin

Question 13

The four quantum numbers

Answer 13

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

Question 14

Aufbau principle

Answer 14

electrons occupy the lowest energy levels first

Question 15

General energy ordering for electrons

Answer 15

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.

Question 16

Hund’s rule

Answer 16

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’

Question 17

Valence electrons

Answer 17

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

Question 18

Predicting ionic charges

Answer 18

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

Question 19

groups and charges

Answer 19

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)

Question 20

periodic table

Answer 20

going across = group
going down = period