DN1). Atomic Structure

Question 1

Neutron

Answer 1

Rel charge, rel size, actual charge(C), actual size(kg)
0 , 1 , 0 , 1.675x10^-27

Question 2

Electron

Answer 2

Rel charge, rel size, actual charge(C), actual size(kg)
-1 , 1/1836 , 1.602x10^-19 , 9.109x10^-31

Question 3

Mass number

Answer 3

Protons + neutrons

Question 4

Proton number

Answer 4

Number of protons or electrons

Question 5

Atoms are….

Answer 5

Neutral

Equal number of protons and electrons

Question 6

Ions are formed by….

Answer 6

Adding or removing electrons

Negative if adding, positive if removing

Question 7

Isotopes are

Answer 7

Atoms with the same number of protons as each other but different number of neutrons

Question 8

Physical properties of isotopes are…

Answer 8

Different

Question 9

Chemical properties of isotopes are…

Answer 9

The same (electrons)

Question 10

How to calculate RFM:

Answer 10

                                Total amount

Question 11

Relative atomic mass (Ar)

Answer 11

Weighted average mass of an atom of an element taking into account all the naturally occurring isotopes relative to 1/12 the relative atomic mass of an atom of carbon 12

Question 12

Use of the time of flight mass spectrometer

Answer 12

Gives accurate information about RFM and isotopic abundance

Helps to identify elements and molecules

Question 13

4 simple steps of a time of flight mass spectrometer

Answer 13

Electrospray ionisation
Acceleration
Ion drift
Detection

Question 14

Electrospray ionisation

Answer 14

Beam of electrons fired at sample –> ionises sample by knocking out an electron
M(g) + e- ———> M+(g) + 2e- (Should happen)
M(g) + e- ———> M2+(g) + 3e- (can happen if electron too energetic)

Question 15

Why is Electrospray ionisation used

Answer 15

Because it reduces the number of molecules that fragment

Question 16

Acceleration

Answer 16

An electric field (negative) attracts the positive ions
The ions accelerate towards it
Some are discharged (if they hit the plate) but some escape through a hole in the plate = beam of positive ions
Ions with the same charge have the same kinetic energy and are travelling at the same speed

Question 17

Ion drift

Answer 17

Ions entering have two variables (charge, z & mass, m)
Time taken = m/z mass charge ratio
Bigger number = longer time of flight

Question 18

Detection

Answer 18

Time of flight detected by computer
Positive ions hits metal plate and pulls off an electron
This generates an electric current
More ions = bigger current , measured by detector

Question 19

Br abundance

Answer 19

50% Br-79, 50% Br-81

Question 20

Cl abundance

Answer 20

75% Cl-35, 25% Cl-37

Question 21

Why are there often small peaks at m/z +1

Answer 21

Because of H-2 and C-13

Question 22

Explain chlorine TOF

Answer 22

(Cl-35—Cl-35)+ 3/4 x 3/4 = 9/16
(Cl-37—Cl-35)+ 3/4 x 1/4 = 3/16 X2 as two ways round
(Cl-37—Cl-37)+ 1/4 x 1/4 = 1/16
So three peaks each separated by two units in the ration 9:6:1

Question 23

RFM=

Answer 23

m/z

Question 24

Relative atomic mass formula=

Answer 24

                  Abundance

Question 25

Relative formula mass from TOF

Answer 25

m/z

Question 26

Sub level s

Answer 26

Number of orbitals 1
Maximum number of electrons 2
Shape Spherical

Question 27

Sub level p

Answer 27

Number of orbitals 3
Maximum number of electrons 6
Shape py, px & pz

Question 28

Sub level d

Answer 28

Number of orbitals 5
Maximum number of electrons 10
Shape -

Question 29

Sub level f

Answer 29

Number of orbitals 7
Maximum number of electrons 14
Shape -

Question 30

The sequence orbitals fill up

Answer 30

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

Question 31

4s sub-shell

Answer 31

Fills before 3d

Empties before 3d

Question 32

Special two which don’t fill as u would expect

Answer 32

Chromium (4s1 3d5 as more stable)

Copper (4s1 3d10 as more stable)

Question 33

Ionisation energy

Answer 33

This involves taking away the outer electron from an atom or ion

Question 34

First ionisation energy

Answer 34

The enthalpy change for removing one more of electrons from one mole of their atoms in gaseous state

Question 35

3 factors that influence ionisation energy

Answer 35

Nuclear charge
Distance of outer electron from nucleus
Shielding

Question 36

Down a group ionisation energy……

Answer 36

Decreases

Question 37

Ionisation energy across a period…

Answer 37

Increases

Question 38

Special phrase

Answer 38

Which is higher in energy therefore electron is easier to remove

Question 39

Proton

Answer 39

Rel charge, rel size, actual charge(C), actual size(kg)
+1 , 1 , 1.602x10^-19 , 1.673x10^-27

Question 40

first ionisation equation

Answer 40

X(g) —–> X(g)^+ + e^-

Question 41

second ionisation equation

Answer 41

X^+ ——> X^2+ + e^- (all with state symbol g)