Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

My AQA Chemistry A Level > 1.1 - Atomic Structure > Flashcards

1.1 - Atomic Structure Flashcards

1
Q

What is the mass of an electron?

A

1/2000

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is mass number?

A

Number of protons and neutrons in the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is an isotope?

A

Atoms with the same number of protons but a different number of neutrons.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What did John Dalton describe atoms as?

A

Solid spheres. Different spheres make up different elements.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What did J.J. Thomson describe atoms as?

A

He discovered electrons and showed that atoms weren’t solid and indivisible. He formed the plum pudding model, with a positively charged “pudding” and negative electrons scattered on it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the gold foil experiment.

A

Ernest Rutherford and his students conducted this experiment. They fired positive alpha particles at a thin sheet of gold. The plum pudding model suggested that most alpha particles would be slightly deflected by the positive pudding. Instead, most of the particles passed straight through and small number were deflected backwards. Most of the atom is empty space.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What was Bohr’s model?

A

Electors exist in shell. When electrons move between shells, electromagnetic radiation is emitted or absorbed. This fitted experimental observations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What was discovered after Bohr’s model?

A

Not all electrons in a shell have the same energy. Sub-shells were included, explaining bonding and ionisation energy trends.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is relative atomic mass /Ar

A

Average mass of an atom of an element compared to 1/12 of a carbon-12 atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is relative isotopic mass? What’s special about it compared to Ar?

A

Mass of an atom of an isotope of an element compared to 1/12 of a carbon-12 atom. Ar is usually not a whole number, whereas relative atomic mass is usually a whole number.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is relative molecular mass/ Mr

A

The average mass of a molecule compared to 1/12 of a carbon-12 atom.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is electrospray ionisation?

A

Dissolve the sample and push through a small nozzle at a high pressure. Apply a high voltage to it. Each particle gains a H+ ion.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the equation for electrospray ionisation?

A

X (g) + H^+ -> XH^+ (g)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is electron impact ionisation?

A

Sample is vaporised and an electron gun fires high energy electrons at it, knocking one electron off each particle to form 1+ ions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What happens in acceleration TOF?

A

Positively charged ions are accelerated by an electric field so they all have the same kinetic energy. Lighter ions move faster than heavier ions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What happens in Ion drift TOF?

A

Ions enter a region with no electric field, so lighter ions drift faster than heavier ions.

17
Q

What happens in detection TOF?

A

Lighter ions reach detector faster than heavier ions (in less time). Detector detects charged particles and forms an electric current when it is hit.

18
Q

What does a mass spectrum tell you?

A

Y axis is abundance, x axis is m/z ratio. If the sample is an element, each line will represent a different isotope. The height of each peak would represent the relative isotopic abundance.

19
Q

What would be the difference in a mass spectrum graph if electrospray ionisation is used?

A

H+ ion is added to each particle. Therefore each peak would be one unit greater than the relative mass of each isotope.

20
Q

How do you calculate Ar from a mass spectrum?

A

(Abundance 1 x m/z 1) + (Abundance 2 x m/z 2)… / total abundance

21
Q

What is the exception in electron configurations?

A

4s before 3d

22
Q

Why are chromium and copper weird? What are their electron configurations?

A

They donate one of their 4s electrons to the 3d sub-shell. It is more stable with a full or half-full d sub-shell.
Cr (24e) - 1s2 2s2 2p6 3s2 3p6 4s1 3d5
Cu (29e) - 1s2 2s2 2p6 3s2 3p6 4s1 3d10

23
Q

What’s different about transition metals in terms of electron configuration?

A

When they become ions, they lose their 4s electrons before their 3d electrons.

24
Q

From left to right on the period table, what are the blocks for the outer shell electrons?

A

S, d, p

25
Q

What decides the chemical properties of an element?

A

Electronic structure.

26
Q

What is first ionisation energy?

A

Energy needed to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.

27
Q

What are the three factors affection ionisation energy? Explain them.

A

Nuclear charge. More protons, stronger nuclear charge and stronger attraction between nucleus and outer electron.
Distance from nucleus. Further away means less attraction between nucleus and outer electron.
Shielding. Increases shielding reduces attraction between nucleus and outer electron.

28
Q

Why does ionisation energy increase within each shell?

A

More protons, stronger nuclear attraction between nucleus and electron. Same shielding.

29
Q

What do big jumps in ionisation energy show?

A

New shell closer to nucleus.

30
Q

Why does ionisation energy decrease down group 2?

A

More number of shells, electrons further distance away from nucleus, more shielding.

31
Q

Across the period, between which groups are the first drop in ionisation energy? Why? Give an example.

A

Groups 2 and 3. There is a drop from magnesium to aluminium. Aluminium’s outer elector is in a 3p orbital, which has a higher energy and more shielding than the outer electron of magnesium which is in a 3s orbital.

32
Q

Where does the second drop occur across the period? Why? Give an example.

A

Between groups 5 and 6. From phosphorus to sulfur, the shielding is identical because the electron is being removed from an identical orbital. In phosphorus the electron is single, and in in sulfur the electron is in a pair. Therefore there is repulsion and it is easier to remove the outer electron from the shared orbital.

33
Q

Where is the second ionisation energy of sulfur compared to phosphorus?

A

Higher

34
Q

Give a reason why the second ionisation energy of silicon is lower than the second ionisation energy of aluminium.

A

Electron in silicon is removed from 3p orbital which has a higher energy than the 3s orbital for the electron in aluminium. Or you could say the electron in silicon is more shielded.

35
Q

What is the technique in exam style questions about ionisation energy?

A

Talk about the orbital that the outer electron is REMOVED from.

36
Q

Why are ionisation energies endothermic?

A

Energy needed to overcome the attraction between the negative electron and positive nucleus.

37
Q

What is important when writing ionisation equations.

A

Remember GASEOUS!

38
Q

Explain how ions are detected and relative abundance is measured in a TOF mass spectrometer.

A

The ions produce a current and gain an electron.
The size of the current determines the relative abundance.

My AQA Chemistry A Level (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions