Unit 1 - Section 1

Question 1

What was Daltons and Thompson’s model of the atom?

Answer 1

The plumb pudding model

Question 2

What was Rutherford model of the atom?

Answer 2

A positive centre surrounded by a negative cloud

Question 3

What did Bohrs discover about the atom?

Answer 3

That electrons had fixed energy shells and going up the shell requires energy and going down them releases energy

Question 4

How to calculate relative atomic masses

Answer 4

Take the weight of the isotope and times it by the abundance, do this for all the isotopes and then add them together. Decide this by 100

Question 5

How does a mass spectrometer works?

Answer 5

1. Electrospray ionisation - the isotopes are all given the same positive charge by knocking off electrons
2. Acceleration - the ions are accelerated by using negatively charged plates. Gives the same kenetic energy to all the ions but because they are different weights they travel at different speeds.
3. Ion drift - the ions travel at a constant speed, the lighter ones traveling at a faster speed
4. Detection - the ions are detected and records how long they drifted for to find a mass/charge value

Question 6

How are electron shells organised?

Answer 6

The shells go

1s2, 2s2, 2p6, 3s3, 3p6, 4s2, 3d10

Question 7

What are the exceptions in electron configuration

Answer 7

Cr rather then being 4s2, 3d4
Cr is actually 4s1, 3d5 as this is more stable

Cu rather then being 4s2, 3d9
Cr is actually 4s1, 3d10

Question 8

What is the ionisation trend down group 2?

Answer 8

It goes down sharply till Ca which it only goes down at a lower rate

Question 9

What are the four stages of time of flight mass spectrometer?

Answer 9

1. Ionisation
2. Acceleration
3. Ion drift
4. Detection

Question 10

How are atoms ionised in mass spectrometry?

Answer 10

Atoms are ionised by knocking of an electron using an electron gun

Question 11

How are ions accelerated in mass spectrometer?

Answer 11

Using increasingly negative plates give all the ions the same kenetic energy

Question 12

Why is ion drift important in mass spectrometry?

Answer 12

Because all the ions have the same kenetic energy the heavier ions move slower because they are heavier

Question 13

How are ions detected in mass spectrometry?

Answer 13

A mettle plate with a current passing through it is hit by the ions and they absorb electrons from the plate. This corses the current to flow and this can be detected