Atoms, ions and compounds

Question 1

Aufbau principle

Answer 1

electrons enter lowest energy orbital available

Question 2

Hund’s rule

Answer 2

electrons prefer to occupy orbitals in their own and only pair up when no empty shells are availible

Question 3

number of orbitals in sublevel s

Answer 3

1

Question 4

number of orbitals in sublevel p

Answer 4

3

Question 5

number of orbitals in sublevel d

Answer 5

5

Question 6

number of orbitals in sublevel f

Answer 6

7

Question 7

ionisation energy

Answer 7

energy required to remove an electron from its shell

Question 8

Order electrons fill up shells

Answer 8

1s 2s 2p 3s 3p 4s 3d 4p

Question 9

Isoelectronic

Answer 9

Species with the same electronic configuration

Question 10

1st ionisation energy

Answer 10

Energy required to remove one electron from each atom in a mole of gaseous atoms producing 1 mole of 1+ gaseous ions

Question 11

2nd ionisation energy

Answer 11

The energy require to remove the 2nd electron from each atom in a mole of gaseous atoms (starting with the 1+ ion)

Question 12

3 Factors affecting ionisation energy

Answer 12

• distance from nucleus (atomic radius)
• nuclear charge
• shielding

Question 13

as you go down a group, 1st ionisation energy…. because….

Answer 13

• decreases

- greater atomic radius, more shedding and less attraction between nucleus and electron

Question 14

as you go across a period, 1st ionisation energy…. because….

Answer 14

• increases

- more protons, same shielding, smaller atomic radius

Question 15

2 dips in the ionisation trend (period)

Answer 15

group 2 to 3 (Mg, Al)

group 5 to 6 (P, S)

Question 16

What causes the dip in the trend between Mg and Al

Answer 16

Al has a higher energy electron (3p) which is slightly further out so if lost more easily

Question 17

What causes the dip in the trend between P and S

Answer 17

P has 1 electron in outer shell, S has 2 which repel each other and so lost more easily

Question 18

degenerate orbitals

Answer 18

those with exactly the same energy

Question 19

principle quantum number

Answer 19

shall number

Question 20

shape of s-orbital

Answer 20

spherical - 2 electrons can be anywhere within the sphere

Question 21

shape of p orbitals

Answer 21

dumbell shaped - move anywhere within the shell

Question 22

4 stages of mass spectrometry

Answer 22

ionisation
acceleration
ion drift
detection

Question 23

2 main techniques of ionisation

Answer 23

electrospray ionisation

electron impact ionisation

Question 24

process of electrospray ionisation

Answer 24

• sample dissolved in solvent
• high voltage is applied
• voltage rips an electron off the solvent and attached it to the sample molecules
• creating positively charged ions

Question 25

main advantage of electrospray ionisation

Answer 25

doesn’t cause fragmentation

Question 26

typical uses of electrospray ionisation

Answer 26

polymers or biological materials - ie. DNA

Question 27

process of electron impact ionisation

Answer 27

• sample is vaporised
• and then hit with electrons from an electron gun
• electrons knock electrons from molecules
• forming positively charged ions

Question 28

process of acceleration of the sample

Answer 28

• molecules are accelerated to the same kinetic energy
• speed as different depending on the mass of the molecule
• lighter particles have a greater velocity and so hit the detector plate first
• lighter particles detected before heavier particles

Question 29

process of ion drift

Answer 29

• time of flight = distance/velocity
• ∴ time = distance x √ m / zKE
• lighter ions take less time as time is dependant on √ m

Question 30

process of detection

Answer 30

• ions hit negatively charged plate
• causes a current, size of current gives a measure if the number of molecules hitting the plate
• gives an abundance of the molecule

Question 31

x-axis of the spectrum

Answer 31

mass/charge ratio

Question 32

y-axis of spectrum

Answer 32

% abundance

Question 33

molecular ion peak

Answer 33

peak of greatest mass/charge ratio

Question 34

smaller peaks in spectrum are due to

Answer 34

isotopes of different masses ∴ different mass/charge ratios

Question 35

smaller, significantly lighter peaks due to

Answer 35

fragmentation of the molecule

Question 36

e. to find RAM of a substance using mass spectrometry

Answer 36

(isotope abundance % x isotope mass )/100

Question 37

2 exceptions of patter of loss of electrons from 4s before 3d

Answer 37

Cr - 4s1 3d5 - energetically favourable to have both half filled

Cu - 4s1 3d10 - energetically favourable to have 3d fully filled

Question 38

orbital

Answer 38

a region around the nucleus that can hold up to 2 electrons

Question 39

how do you determine the mass of an isotope

Answer 39

using a mass spectrometer

Question 40

how does a mass spectrometer work?

Answer 40

• sample vaporised
• then ionised to form positive ions
• ions accelerated - heavier = slower + more difficult to deflect
• ions detected on mass spectrum as a mass-to-charge
• ratio is equivalent to relative isotopic mass

Question 41

how calculate mass-to-charge ratio?

Answer 41

mass of ion/charge of ion

Question 42

polyatomic ion

Answer 42

ion formed of atoms of more then 1 element bonded together

Question 43

binary component

- eg.

Answer 43

2 elements only

- sodium oxide