physical chemistry

Define the term relative atomic mass.

The average mass of an atom of an element compared to 1/12th the mass of on atom of carbon-12

Explain why the atomic radius decreases across Period 3, from sodium to chlorine

The number of protons increases OR nuclear charge increases

Shielding is similar/same OR electrons are added to the same shell

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

ion hits the detector and gains an electron. (relative) abundance is proportional to (the size of) the current

State why iodine does not conduct electricity.

No delocalised electrons

Describe how the molecules are ionised using electrospray ionisation.

Sample is dissolved (in a volatile solvent)

(Injected through) nozzle at high voltage

Each molecule/particle gains a proton/H+

State and explain the general trend in first ionisation energy across Period 3.

General increase

Greater nuclear charge / more protons

Same shielding / electrons added to same shell

Stronger attraction (from nucleus) for outer electron(s)

What is the importance of percentage yield?

The idea of getting as much product as possible in the reaction

What is the importance of atom economy ?

The idea of maximising the mass of reactants .