Atomic Structure

Question 1

isotopes

Answer 1

atoms have the same number of protons, but a different number of neutrons

Question 2

electronspray ionisation

Answer 2

dissolve the smple in a polar volatile sample and then spray through a fine needle
- it gains a protons

Question 3

electron impact

Answer 3

high energu electrons from an electron gun

fired at sample and knocked off an electron

Question 4

how ions are accelerated in TOM

Answer 4

• by electrical field to create a consant KE

Question 5

how ions are seperated in TOM

Answer 5

• depending on their mass
  heavier travel slower and lighter take longer

Question 6

how ions are detected in TOM

Answer 6

• greater current that is directly proptional to the abundance.
  pick up an electron and generate current
• bigger the current = more isotopes

Question 7

why is it important to ionise molecles in TOM

Answer 7

-only ionise will interact with on be acclerated by an eletrical field
-only ions will create a current when hitting the detector
- picked up on a negative plate of a detector so must be interact and positvely charged

Question 8

equations mass of an ions in kg

Answer 8

mass divide by 6.022x10^23 divide by 1000

Question 9

define realtive atomic mass

Answer 9

is the average mass of one atom of an element compared to 1/12 th of mass of carbon 12

Question 10

electron impact ionsation peak

Answer 10

mr of sample = peak with greatest m/z

Question 11

elctrospray ionisation peak of mr

Answer 11

mr =greatest m/z value -1

Question 12

first ionisation energy

Answer 12

the min amount of energy required to remove an electron from gaseous atom

Question 13

trend down the groups

Answer 13

• size of atom increase
• more principal energy level
• outer electon being futhe away from nucleus
• less attraction betwen the nucleus and outer electron
• more sheilding

Question 14

trend across the periods

Answer 14

• same shielding
• proton increase
• nuclear charge increase
• stronger attraction between he nucleus and outer electron
  -decreases atomic radius

Question 15

deviation accross period why first ionisation energy of Al is less tan Mg

Answer 15

• Al is removed from 3p sublevel
• Mg is removd from 3s
  3p is higher energy than 3s
  Al outer electron i further away from the nucleus and less attracted so less energy is needed

Question 16

deviation accross the periods between S and P

Answer 16

-same pinciple eneergy level 3p
- sulfur has a pair of electron
- increasing repulsion between the elctrons
- so less energy is needed to remove he outer electron