3.1.1 atomic structure Flashcards
(22 cards)
plum pudding model
A sphere of positive charge, with small negative charges distributed evenly within it.
electron shell model
A small, dense nucleus surrounded by orbiting electrons in electron shells.
relative atomic mass
The average mass of an atom of an element, compared to 1/12 of the mean mass of an atom of 12C.
relative molecular mass
The average mass of an element of a molecule, compared to 1/12 of the mean mass of an atom of 12C.
isotope
why do they react in the same way
- An atom of the same element with a different number of neutrons.
- Their proton number and electronic configuration is the same.
ions
Formed when an atom of an element either loses or gains electrons.
mass spectrometer
Used to determine the RAM of an element. It can find the abundance and mass of each isotope in an element, and the relative molecular mass of substances made of molecules.
ionisation
A sample of an element is vaporised and injected into MS, and a high voltage is passed across the chamber, causing electrons to removed from the atoms.
acceleration
The positively charged ions are accelerated towards a negatively charged detection plate. This gives all ions a constant KE.
ion drift
The ions are deflected by a magnetic field into a curved path. The radius of their path is dependent on the charge and mass of the ion.
detection
When the positive ions hit the negative detection plate, they gain an electron producing a flow of charge. greater abundance = greater current.
analysis
These values are used in combination with the flight time to produce a spectra print out with the relative abundance of each isotope displayed.
RAM
Ar = (m/z x abundance)
(total abundance)
electron orbital
The space an electron cloud fills. Each orbital holds up to 2 electrons.
types of orbitals
s - spherical
p - dumbbell
d - clover
exceptions
If electron spins are unpaired and unbalanced, it produces a natural repulsion, making the atom unstable.
ionisation energy
The minimum energy required to remove one mole of electrons from one mole of atoms in a gaseous state - measured in kJmol-1.
successive ionisation energy
Requires more energy since as electrons are removed, electrostatic FoA between electron and nucleus increases, so more energy is needed to overcome it.
factors affecting it
- Distance between nucleus and outermost electron
- Charge on nucleus
- Shielding (
trend down a group
FIE decreases, because atomic radius increases, and shielding also increases.
trend down a period
- FIE increases, because nuclear charge increases as the number of protons increases, and the shielding remains similar.
exceptions
- Higher subshell - requires less energy to remove.
- Takes less energy to remove electron from pair, since they repel each other.
