T1- Atomic Structure Flashcards
(10 cards)
What are isotopes?
Elements with the same number of protons but different number of neutrons.
Who proposed the Plum Pudding Model?
J.J Thompson
What was the Plum Pudding Model described as?
A solid, positively charged sphere with negative electrons dotted in it.
3 findings of the Rutherford scattering experiment?
Nucleus was small and dense, nucleus was positive, atom was mostly empty space.
What is relative atomic mass?
The average mass of an atom of an element, compared to 1/12th the mass of an atom of carbon-12.
4 stages of mass spectrometry:
Ionisation, acceleration, ion drift and detection.
What is electrospray ionisation?
A sample is dissolved in a polar solvent, a high voltage is applied and each particle gains a H+ ion to become a gas of positive ions.
What is electron impact ionisation?
Sample is vaporised, an ‘electron gun’ fires high energy electrons at it, knocking off an electron of each atom in the sample to form positive ions.
What is first ionisation energy?
The energy needed to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions. Equation: M (g) —- M+ (g) + e^-
Why does ionisation energy decreases down the group?
Larger atomic radius and more shielding outweighs higher nuclear charge. Lower attraction between valence electrons and nucleus.
