Atomic Structure

current model of atom

Protons and neutrons in the nucleus

electrons in different orbitals/ energy orbitals

Mass number

The number of protons and neutrons in the nucleus of the atom

two reasons why it is necessary to ionise the isotopes of chromium before they can be analysed in a TOF mass spectrometer

ions will interact with and be accelerated by an electric field

Ions create a current when hitting the detector

Electrospray ionisation

sample is dissolved in a volatile solvent injected through a hypodermic needle at high voltage power supply

each molecule gains a proton

forming a +1

pattern in first I.E of elements Li —> Ne

1st I.E increases, increased nuclear charge, similar shielding, electrons in same energy level, stronger attraction between nucleus and outer electron

Deviation Be —> B: B is lower than Be, outer e- in 2p, higher in energy than 2s

Deviation N —> O: O lower than N, 2e- in 2p need to pair, pairing causes repulsion

which element Mg and Al has the lowest first I.E

Al

outer e- in 3p subshell

higher in energy from the nucleus

FIRST I.E of elements in G2 from Mg to Ba

decreases

nuclear charge decreases

IONS get larger

shielding increases

weaker attraction of ion to lost e-

outline how the TOF mass spectrometer is able to separate these two species to give two peaks

positive ions are accelerated by an electric field

to a constant K.E

the positive ions with m/z of 104 have the same KE as those with m/z of 118 and move faster

therefore, ions with m/z of 104 arrive at the detector first