Atomic Structure

Question 1

Mass of proton

Answer 1

1

Question 2

Mass of neutron

Answer 2

1

Question 3

Mass of electron

Answer 3

1/1800

Question 4

Charge of proton

Answer 4

+1

Question 5

Charge of neutron

Answer 5

0

Question 6

Charge of electron

Answer 6

-1

Question 7

Atomic number

Answer 7

number of protons in the nucleus

Question 8

Mass number

Answer 8

Total number of protons and neutrons

Question 9

Isotopes

Answer 9

Atoms with the same number of protons but different number of electrons

Question 10

Reason mass spec is done under a vacuum

Answer 10

Otherwise air particles would ionise and be detected

Question 11

Steps of mass spec

Answer 11

Ionisation, acceleration, drift, detection

Question 12

Electron impact ionisation

Answer 12

High energy electrons are fired at a vaporised sample removing an outer electron forming positive ions

Question 13

Electrospray ionisation

Answer 13

Sample is dissolved in a volatile, polar solvent and injected through a fine needle. The tip of the needle has a high voltage adding a proton to the sample. M(g) + H= –> MH+

Question 14

Use of electron impact

Answer 14

elements and substances with low formula mass. Larger molecules may fragment

Question 15

Use of electrospray ionisation

Answer 15

larger organic molecules as fragmentation is less likely

Question 16

Acceleration

Answer 16

Positive ions are accelerated by an electric field to a constant kinetic energy = 1/2 m v2

Question 17

Flight Tube/ Drift region

Answer 17

Lighter ions move down the tube quicker than heavier ones and are distinguished by flight times

Question 18

Detection

Answer 18

positively charged ions are attracted to a negatively charged plate generating a current, which a computer analyses. The more ions of a particular size, the larger the current produced

Question 19

Relative atomic mass

Answer 19

weighed average of all isotopes of an atom compared to 1/12th mass of a C-12 atom

Question 20

Relative atomic mass calculation

Answer 20

(mass 1 x abundance 1) + (mass 2 x abundance 2) + … / total abundance

Question 21

What is the relative atomic mass for Mg?
Mg-24 = 78.70%, Mg-25 = 10.13%
Mg-26 = 11.17%

Answer 21

24.3

Question 22

Key features to include when asked for species for a peak on a mass spectrum

Answer 22

charge and mass number. e.g. 24Mg+

Question 23

Calculate the relative atomic mass of Te. Te-124 = 2, Te-126 = 4, Te-128 = 7, Te-130 = 6

Answer 23

127.8

Question 24

Copper has 2 isotopes 63-Cu and 65-Cu. The RAM is 63.5. What is the abundance of each isotope

Answer 24

63-Cu = 72.5%
65-Cu = 27.5%

Question 25

Molecular Ion Peak

Answer 25

Shows the relative molecular mass and is the peak furthest to the right

Question 26

Order sub shells are filled --> 5p

Answer 26

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

Question 27

Electronic structure for Ca

Answer 27

1s2, 2s2, 2p6, 3s2, 3p6, 4s2

Question 28

s block element

Answer 28

element with highest energy electron in an s sub shell (first two groups of PT)

Question 29

p block element

Answer 29

element with highest energy electron in an p sub shell (end 6 groups of PT)

Question 30

d block element

Answer 30

element with highest energy electron in an d sub shell (central section of PT)

Question 31

electronic configuration for Sc

Answer 31

[Ar] 4s2, 3d1

Question 32

electronic configuration for Ti

Answer 32

[Ar] 4s2, 3d2

Question 33

electronic configuration for V

Answer 33

[Ar] 4s2, 3d3

Question 34

electronic configuration for Cr

Answer 34

[Ar] 4s1, 3d5

Question 35

electronic configuration for Mn

Answer 35

[Ar] 4s2, 3d5

Question 36

electronic configuration for Fe

Answer 36

[Ar] 4s2, 3d6

Question 37

electronic configuration for Co

Answer 37

[Ar] 4s2, 3d7

Question 38

electronic configuration for Ni

Answer 38

[Ar] 4s2, 3d8

Question 39

electronic configuration for Cu

Answer 39

[Ar] 4s1, 3d10

Question 40

electronic configuration for Zn

Answer 40

[Ar] 4s2, 3d10

Question 41

electronic configuration for Ti3+

Answer 41

[Ar] 3d1

Question 42

electronic configuration for V3+

Answer 42

[Ar] 3d2

Question 43

electronic configuration for Cr3+

Answer 43

[Ar] 3d3

Question 44

electronic configuration for Mn2+

Answer 44

[Ar] 3d5

Question 45

electronic configuration for Cu2+

Answer 45

[Ar] 3d9

Question 46

electronic configuration for Zn2+

Answer 46

[Ar] 3d10

Question 47

Rules for filling orbitals

Answer 47

Fill lowest energy orbitals first. Singly fill orbitals before doubly filling

Question 48

Rules for filling and emptying d block element sub-shells

Answer 48

Fill 4s before 3d. Empty 4s before 3d.

Question 49

First Ionisation Energy

Answer 49

Energy required to remove one mole of electrons from one mole of gaseous atoms to form one mole of gaseous 1+ ions

Question 50

Equation for first ionisation energy

Answer 50

X(g) --> X+(g) + e

Question 51

Second Ionisation Energy

Answer 51

Energy required to remove one mole of electrons from one mole of gaseous 1+ ions to form one mole of gaseous 2+ ions

Question 52

Second ionisation energy equation

Answer 52

X+(g) --> X2+(g) + e

Question 53

Factors that affect ionisation energy

Answer 53

Amount of protons, distance of electrons from nucleus and amount of shielding

Question 54

Why are successive ionisation energies always larger?

Answer 54

2nd IE is larger than 1st IE because the electron is being removed from a 1+ ion with greater attraction to the outgoing electron.

Question 55

What does a big jump in successive ionisation energy show?

Answer 55

A change of shell that the electron is being removed from. E.g. a big jump from electron 4 to 5 indicated the element is in group 4 with 4 electrons on the outer shell

Question 56

``` What group is this element in? 1st IE = 590 2nd IE = 1150 3rd IE = 4940 4th IE = 6480 5th IE = 8120 ```

Answer 56

Group 2

Question 57

How does IE change down a group?

Answer 57

Decreases - despite having more protons, the elements have a greater distance from the nucleus to the outgoing electron with more shielding

Question 58

What is the general trend in IE across a period

Answer 58

Increases - successive element have more protons but the electrons are added to the same shell with the same amount of shielding and slightly less distance between the outer shell and the nucleus

Question 59

Why is there a drop in IE from Mg to Al?

Answer 59

The outermost electron in Al is in a 3p orbital compared to 3s in Mg so is slightly further away from the nucleus with more shielding so easier to remove.

Question 60

Why is there a drop in IE from P to S?

Answer 60

The outermost electron in S is in a paired 3p orbital compared to singly filled 3p in P. This means there is some repulsion from the other electron making it easier to remove.