1.1 Atomic structure

Question 1

Define an isotope

Answer 1

Isotopes of an element are atoms with the same number of protons but different numbers of neutrons

Question 2

Define relative atomic mass

Answer 2

The relative atomic mass is the average mass of an element divided by a twelfth of the mass of an atom of carbon-12

Question 3

Outline and name the first stage in mass spectroscopy

Answer 3

Vapourisation and ionisation is where a sample is dissolved in a volatile solvent and injected through a fine hypodermic needle which is highly positivly charged. The sample is injected into a vacuum, the solvent dissloves and leaves +1 ions of the sample.

Question 4

Define and outline the second stage in mass spectroscopy

Answer 4

Acceleration of ions is where the ions are accelerated with the same kinetic energy using an electric field.

Question 5

Define and outline the third stage in mass spectroscopy

Answer 5

Seperation of ions is where the accelerated ions enter the time of flight chamber. Ligthter ions travel faster and heavier ions travel slower. We can say their time of flight was either greater or smaller.

Question 6

Define and outline the fourth stage in mass spectroscopy

Answer 6

Detection is where the ions hit a negatively charged plate which is part of a circuit. The more ions that hit the plate, the greater the surge in current. This can be plotted on a graph to show the abundance of certain isotopes of an element.

Question 7

Name the 4 sub energy levels in order and how many electrons they can contain

Answer 7

s-2

p-6

d-10

f-14

Question 8

What are the two rules for electrons in energy sub levels?

Answer 8

1. Electrons are always added to the energy level which requires the least energy.
2. Electrons are always removed from the highest sub level.

Question 9

In what order are electron sub levels filled?

Answer 9

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

Question 10

In what situations are electrons moved between sub levels (Cu and Cr)?

Answer 10

When the 3d sub level is one electron from half full or full an electron is moved from the 4s shell into it to fill it up as it is more stable like that.

Question 11

Define the first ionisation energy

Answer 11

The first ionisation energy is the energy needed to remove one mole of electrons from one mole of gaseous atoms.

Question 12

What 3 factors affect ionisation energy?

Answer 12

1. Nuclear charge (no. of protons in the nucleus)
2. Distance from nucleus
3. Shielding from full outer shells of electrons

Question 13

What is the general trend for successive ionisations of an element?

Answer 13

The energy required goes up by a small amount for every electron removed and a large amount for every new shell that the electrons are being removed from.

Question 14

What is the general trend of ionisations energies as you go down a group?

Answer 14

The ionisation energies decrease as there is more shielding for every element you go down.

Question 15

What is the general trend for first ionisation energies as you go across a period?

Answer 15

The energies increase as the nuclear charge is increased.

Question 16

Why is there troughs at Al and S?

Answer 16

At Al the 3s shell has been filled and the 3p shell is starting to be filled. At S the 3p shell is half full.