Atomic structure

Question 1

define relative mass

Answer 1

the mass of particles compaared to a proton

Question 2

define mass number

Answer 2

proton number + neutron number

Question 3

define relative atomic mass

Answer 3

the average mass of an atom relative to 1/12 of a carbon 12 atom

Question 4

do isotopes react the same as atoms, why

Answer 4

yes, they have the same electron configuration

Question 5

how do you calculate relative atomic mass

Answer 5

total number of all atoms

AKA

total abundance

Question 6

what is the mass spectrometer used for

Answer 6

to determine the relative atomic mass

Question 7

what does the time of flight mass spectrometer detect

Answer 7

the mass and relative abundance of iosopts in elements

Question 8

what condition must the TOF mass spectrometer be used in

Answer 8

a vacum so that ions dont colide with air molecules

Question 9

what are the 4 stages of the TOF mass spectrometer

Answer 9

ionisation
acceleration
flight tube drift
detection

Question 10

what are the two type of ionisation used for the TOF mass spectrometer and what are they used for

Answer 10

electron impact method - elements
electrospray method - large molecules

Question 11

what happens during electron impact ionisation (3)

Answer 11

• sample is vaporised
• an electron gun (current carrying wire) emits high energy electrons that knock electrons of the elements
• forms a 1+ ion

Question 12

what happens during electrospray ionisation (4)

Answer 12

• sample is disolved
• sample pass through a hypodermic needle attached to postive high voltage power
• producs 1+ charged droplets
• Solvent evaporates from droplets in the vacum to form a fine mist

Question 13

what happens during acceleration in a TOF mass spectrometer (2)

Answer 13

• ions are accelerated by an electric field so they all have the same KE
• lighter and more highly charged ions achieve a higher speed

Question 14

what happends during flight tube drift in a TOF mass spectrometer (3)

Answer 14

• ions travel in a beam
• attracted to the negatively charge detector plate
• the ions travel at different speeds so take different times to reach the detector

Question 15

which types of ions reach the detector first in a TOF mass spectrometer

Answer 15

lighter ions

Question 16

what happens during detection in a TOF mass spectrometer (2)

Answer 16

• positive ions hit a negaitvely charged plate
• every collision produces an electric current proportional to the number of ions

Question 17

what type of data does the TOF mass spectrometer produce

Answer 17

a mass spectrum

Question 18

what are the two axis on a mass spectrum

Answer 18

x axis = m/z (mass to charge ratio)
typically just the mass of a particle as charge = 1

y axis = percentage / relative abundance

Question 19

what do the number of peaks represent on a mass spectrum

Answer 19

the number of isotopes present

Question 20

how do you predict the amount of peaks on a mass spectrum

Answer 20

work out the number of possible isotopes combinations

Question 21

what is an orbital

Answer 21

a region where it is likely to find an electron
one orbital can hold 2 electrons

Question 22

how many electrons can fit in the s sub level

Answer 22

2

Question 23

how many electrons can fit in the p sub level

Answer 23

6

Question 24

what does the s sub level look like

Answer 24

a sphere

Question 24

what does the p sub level look like

Answer 24

a funny flower with 6 petals 3 orbitals

Question 24

how many electrons can the d sub level hold

Answer 24

10

Question 25

how many electrons can the f sub level hold

Answer 25

14

Question 26

how many electrons can the follow energy levels hold 1 2 3 4

Answer 26

1 - 2 2 - 8 3 - 18 4 - 32

Question 27

do electrons pair to in an orbit to begin with

Answer 27

no, they fill all the orbitals with one, then pair

Question 28

what is the order of energy levels being filled.

Answer 28

1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d

Question 29

how is the electron configuration of Chromium and copper different from normal

Answer 29

an electron is promoted from 4s and is transfered to 3d (4s has one electron and 3d has 1 electron in each orbital)

Question 30

what happens when transition metals lose electrons

Answer 30

they lose them from 4s first, then 3d

Question 31

define first ionisation energy

Answer 31

the energy require to remove one mole of electrons from one mole of gaseous atoms to produce one mole of gaseous 1+ ions

Question 32

what is the equation for the first ionisation energy of sodium

Answer 32

Na -> Na+1 + e-

Question 33

how would you write the second ionisation energy of sodium

Answer 33

Na+ -> Na+2 + e-

Question 34

how can you tell a new energy level has been reached based on successive ionisation energies, how can you tell the group number based on this

Answer 34

there will be a big jump in energy the group number will be the number of ionisation energies before the big jump

Question 35

why does ionisation energy decrease going down a group

Answer 35

- more shells - more electron shielding - greater distance between the outer shell electrons and nucleus - less attraction between nucleus and outer electrons

Question 36

what happens to atomic radius going down a group? going across a period?

Answer 36

down a group - always increases across a period - generally decreases

Question 37

why does ionisation energy generally increase as you go along a period

Answer 37

- number of protons is greater, so nucleur charge is greater

Question 38

why do first ionisation energies dip as you enter a new sub level

Answer 38

- the electron is alone, so easier to lose - electron is further from the nucleus

Question 39

why do first ionisation energies dip when an element has more paired electrons in its sub levels

Answer 39

the electron is repelled by its paired electron, so loses it easier