Unit 1-Atomic Structure

Question 1

Masses and charges of subatomic particles

Answer 1

Proton - mass of 1 - +1 charge
Electron - negligible mass - -1 charge
Neutron - mass of 1 - neutral charge

Question 2

Properties of neutrally charged/ionised atoms

Answer 2

In neutral atoms No. Electrons is equal to No. protons, ionised atoms have an overall charge due to an imbalance

Question 3

Difference between isotopes of the same element?

Answer 3

Isotopes have different number of neutrons, changing their mass but not their charge or electronic structure

Question 4

3 different models of the atom

Answer 4

Plum Pudding - solid ball of positive material with electrons dotted in like plums in a pudding

Rutherfords- includes fact that atom is mostly empty space with a tiny positive nucleus being orbited by electrons

Bohr’s- suggested electrons contained in specific energy levels instead of a cloud, and that radiation is released when they move between levels

Question 5

Process of mass spectrometry

Answer 5

• sample is ionised
• an electric field applies equal amounts of kinetic energy to all ions
• the lighter ions accelerate faster through the spectrometer than the heavy ones, and hit the detector faster
• they take the electron back when they hit the detector, causing a current
• mass/charge ratio calculated and used to produce a graph of relative abundance against m/z

Question 6

How are atoms ionised in mass spectrometers?

Answer 6

Either by being dissolved in a solvent and pressurised under a high voltage or being hit with a high velocity electron gun

Question 7

How to read spectrometry graphs

Answer 7

Height of peak = relative abundance
Mr can be calculated for each isotope using %abundance×mass, or (exact abundance×mass) of every value ÷ total abundance of every value

Question 8

All four sub shells, no. Of orbitals and max electrons

Answer 8

S-1 orbital-2 electrons
P-3 orbitals-6 electrons
D-5 orbitals-10 electrons
F-7 orbitals-14 electrons

Question 9

Electron Shells, sub shells in each one, max electrons per shell

Answer 9

1- 1s - 2
2- 2s,2p - 8
3- 3s,3p,3d -18
4- 4s,4p,4d,4f -32
5 - ditto

Question 10

How to correctly write electronic structure

Answer 10

Split total number of electrons into the individual shells and sub shells, and write them in order going out from the nucleus. Include the number of electrons in each shell. E.g 1s2, 2s2, 2p3

4s fills before 3d, 5s fills before 4d, 5p before 4f

Question 11

Ionisation energy definition

Answer 11

The total energy needed to remove one electron from one mole of a gaseous substance

Question 12

What affects ionisation energy?

Answer 12

• Strength of nucleus’ positive charge
• Distance of electron from nucleus
• Number of electron Shells shielding nuclear charge between nucleus and electron
• Electrons are easier to take from higher energy levels, and easier to remove from paired orbitals (one removed from each full orbital first before second)