1 - Atomic Structure - AQA A-level Chemistry

Relative Isotopic Mass

The mass of an atom of an isotope relative to 1/12 of the relative atomic mass (Ar) of an atom of Carbon-12

Isotope

Isotopes are atoms with the same atomic number (number of protons) and electron configuration but different number of neutrons —> different mass number

How does an isotope’s chemical and physical properties differ from an atom of the same element?

Isotopes have the same electron configuration so it still has the same chemical properties.

Different numbers of neutrons results in a different mass which can affect physical properties.

Ion

Describe the structure of an atom in terms of subatomic particles (mark?)

bullet points for each point

First ionisation energy

The energy required to remove one electron from each atom in one mole of gaseous atoms

Electron shielding

The repulsion of outer electrons by inner-shell electrons reducing nuclear attraction

Mass spectrometer

An instrument used to measure the mass-to-charge ratio of ions

Time of flight (TOF)

The time taken for ions to travel through the mass spectrometer to the detector