1
Q
Position of the proton in an atom?
A
Nucleus
2
Q
Position of the neutron in an atom?
A
Nucleus
3
Q
Position of the electron in an atom?
A
Orbitals
4
Q
Relative mass of a proton?
A
1
5
Q
Relative mass of a neutron?
A
1
6
Q
Relative mass of a electron?
A
1/1840
7
Q
Relative charge of a proton?
A
+1
8
Q
Relative charge of a neutron?
A
0
9
Q
Relative charge of a electron?
A
-1
10
Q
What is the atomic number?
A
The number of protons in the atom.
11
Q
What is the mass number?
A
The total number of protons and neutrons in the atom.
12
Q
What is an isotope?
A
Atoms with the same atomic number but different number of neutrons.
13
Q
Describe the chemical and physical properties of isotopes.
A
Isotopes have similar chemical properties because they have the same electronic structure.
Isotopes have different physical properties because they have different masses.
14
Q
What are the 4 energy levels?
A
S
P
D
F
15
Q
How many electrons does the s orbital hold?
A
2
16
Q
How many electrons does the p orbital hold?
A
6
17
Q
How many electrons does the d orbital hold?
A
10
18
Q
How many electrons does the f orbital hold?
A
14
19
Q
What is represented by the arrows spinning in opposite directions?
A
Different spins of the electrons in the orbital.
20
Q
What shape is the s sublevel?
A
Spherical
21
Q
What shape is the p sublevel?
A
Dumbbell
22
Q
What does an arrow represent?
A
One electron.
23
Q
What does the box holding two arrows represent?
A
One orbital
24
Q
How do the boxes fill up?
A
One arrow for each box then put a second arrow after all boxes have atleast 1.
25
When a positive ion forms, what happens to the outermost shell?
An electron is lost.
26
When a negative ion forms, what happens to the outermost shell?
An electron is gained.
27
Does 4s or 3d fill first?
4s
28
What is different about copper and chromium?
3d fills before 4s.
29
Define first ionisation energy.
The minimum energy needed to remove one mole of electrons from one mole of atoms in the gaseous state to form one mole of gaseous ions.
30
Give the equation of the first ionisation energy for H.
H(g) -> H^+(g) + e-
31
Define second ionisation energy.
The amount of energy needed to remove a second mole of electrons from a gaseous ion with a 1+ charge to form a gaseous ion with a 2+ charge.
32
Give the equation of the second ionisation energy for H.
H^+ (g) -> H^2+ (g) + e-
33
3 factors affecting ionisation energy?
Nuclear charge
Atomic Radius
Shielding
34
What is the nuclear charge?
The attraction of the nucleus. The more protons in the nucleus, the greater the attraction.
35
What is the atomic radius?
The distance of the outermost electrons to the nucleus. The bigger the atom, the weaker the attraction to the nucleus.
36
What is shielding?
The effect where inner electrons reduce the attraction between the nucleus and outermost electrons.
37
Trend across a period for shielding.
Stays the same.
38
Trend down a group for shielding.
Increases.
39
Why do first ionisation energies decrease down a group?
Atomic radius increases - less electrostatic attraction between nucleus and outermost electrons.
Shielding increases
Weaker attraction between nucleus and outermost electrons - less energy to remove electrons.
40
Why is there a general increase in first ionisation energy across a period?
Nuclear charge increases (stronger attraction between nucleus and outer electrons)
Shielding has no change (they’re in the same electron shell)
Greater attraction (due to nuclear charge meaning more energy is required to remove electrons)
41
What is m/z
Mass to charge ratio
42
How is relative atomic mass calculated.
Sum of (isotopic mass x relative abundance) divided by total relative abundance.
43
What are the two isotopes of chlorine?
Chlorine 35
Chlorine 37
44
What is the percentage abundance of chlorine 35?
75%
45
What is the percentage abundance of chlorine 37?
25%
46
What are the two isotopes of bromine?
Br 79
Br 81
47
What is the percentage abundance of Br 79?
50%
48
What is the percentage abundance of Br 81?
50%
49
What was the plum pudding model?
Atoms consisted of a sphere of positive charge with small negative charges distributed evenly within it.
50
Who discovered the most recent electron shell model?
Rutherford
51
How to calculate the maximum number of orbiting electrons that can be held by any single shell? Where n is the number of shells.
2n^2
52
What is relative atomic mass?
The mean mass of an atom of an element divided by one twelfth of the mean mass of an atom of the carbon-12 isotope.
53
Why do isotopes react chemically in the same way?
Their proton number and electron configuration are the same.
54
When is an ion formed?
When an atom loses or gains electrons meaning it'll have an overall charge.
55
Why do electrons pair up with the opposite spin?
So that the atom is as stable as possible.
56
What happens if the electron spins are unpaired?
They'll be unbalanced and produce a natural repulsion between the electrons making the atom very unstable. The electrons may take on a different arrangement to improve stability.
57
What kind of process is ionisation energy?
Endothermic.
58
What are successive ionisation energies?
Second ionisation energy, third ionisation energy etc. Each successive ionisation energy is greater than the previous.
59
Why is each successive ionisation energy greater than the previous?
As electrons are removed (creates a more positively charged ion), the electrostatic force of attraction between the positive nucleus and negative outer electron increases. More energy is needed to overcome this attraction.
60
When successive ionisation energies are plotted on a graph, what does the sudden large increase indicate?
A change in energy level. This is because the electron is being removed from an orbital closer to the nucleus so more energy is required to do so.
61
State which of the elements magnesium and aluminium has the lower first ionisation energy.
Explain your answer.
Aluminium.
Outer electron is in the 3p orbital.
It is further from the nucleus so it is easier to remove.
62
Describe how the molecules are ionised using electrospray ionisation.
1) Sample is dissolved in a volatile solvent.
2) Injected through a needle at high voltage.
3) Each molecule gains a proton.
63
Equation for electrospray ionisation?
X(g) + H+ -> XH+(g)
64
Describe electron impact.
1) A vaporised sample is injected at low pressure.
2) An electron gun fires high energy electrons at the sample.
3) This knocks out an outer electron.
4) This forms positive ions with different charges.
65
Equation for electron impact?
X (g) --> X^+(g) + e-
66
What are the 5 steps for a time of flight mass spectrometer?
1) Ionisation
2) Acceleration
3) Ion drift
4) Detection
67
What are the two techniques for ionisation?
Electrospray ionisation or electron impact.
68
What is electron impact used for?
Elements and substances with a low formula mass. It can cause larger organic molecules to fragment.
69
What is electrospray ionisation used for?
Larger organic molecules. The softer conditions of this technique means fragmentation doesn't occur.
70
What is a mass spectrometer used for?
To identify different isotopes and find the overall relative atomic mass of an element.
71
What condition does the time of flight mass spectrometer have to be in?
Under a vacuum otherwise air particles would ionise and register on the detector.
72
What is acceleration?
These positively charged ions are then accelerated towards a negatively charged detection plate.
73
Given that all the particles have the same kinetic energy, what is the velocity of each particle dependent on?
Its mass. Lighter particles have a faster velocity and heavier particles have a slower velocity.
74
What is ion drift?
The ions are then deflected by a magnetic field onto a curved path. The radius of their path is dependent on the charge and mass of the ion.
75
What is detection?
When the positive ions hit the negative detection plate, they gain an electron producing a flow of charge. The greater the abundance, the greater the current produced.
Physical Chemistry
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