Atomic Structure Flashcards
What does a T.O.F Mass Spectrometer do?
Detects the mass + relative abundance of isotopes
What happens during electron impact ionisation?
- Sample heated - vapourised
- sample bombarded with electrons from electron gun and knocks an electron off
X (g) + e- –> X+ (g) + 2e-
What happens during electrospray ionisation?
- Sample dissolved in a volatile solvent
- Turned into a fine spray via a charged needle
- H+ gained from solvent
What happens during the acceleration stage of T.O.F?
- Charged plates create an electric field
- All ions accelerated forwards with the same kinetic energy
- have different velocities dur to differences in mass
What happens during the detection stage of T.O.F?
- Negatively charged detector
- +ive ions gain electrons at the plate, which causes an electrical current
- The current is monitored and analysed to give a SPECTRA
How would you calculate an unknown isotopes atomic mass?
Ar = ∑(percentage isotope abundance)/100
What is the formula for kinetic energy?
K.E = 1/2 MV^2
What is 1st molar ionisation energy?
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms
Why does 1st Molar Ionisation Energy decrease going down a group?
- The atomic radius increases
- The distance between the nucleus and outer e- increases
- Shielding increases ∴ attraction between the nucleus and the outer electrons decreases ∴ Less energy is required to remove the outer e-
Why does 1st molar ionisation energy increase across the period?
- Nuclear charge increases
- There is no change in the amount of shielding or distance of the outer e- from the nucleus
- Attraction between outer e- and nucleus increases
- More energy is needed to remove the outer e-
What is the general trend in 1st molar ionisation energy?
There is a general increase in 1st molar i.e across a period
