CAT Parker Flashcards
Relative mass of electron
1/1840
Who proposed the idea of elements?
Robert Boyle
Who suggested that elements were made up of atoms?
John Dalton
Who discovered radioactivity?
Henri Becquerel
Who discovered electrons?
JJ Thompson
Who discovered the nucleus?
Ernest Rutherford
Who discovered the neutron?
James Chadwick
Relative atomic mass
Average mass of one atom / 1/12 of a carbon-12 atom
Why does the second electron require more ionisation energy than the first?
It is being removed from a charged ion
First ionisation energy
The first Ionization Energy is the energy needed to remove one mole
of electrons from one mole of gaseous atoms.
A general equation is:
M(g) → M+(g) + e-
Why does sulphur have a lower FIE than phosphorus?
Sulphur electron is paired so repulsed
Why is an electron promoted to 3d in the case of Cr and Cu
A half filled or fully filled d sub-level is more stable.
Which equation are required for tof mass spectrometry questions?
KE=1/2mv^2
t=d/v
Why does 4s fill before 3d
The 4s energy sub-level is lower in energy than the 3d.
What are the two methods of creating positive ions?
Electrospray ionisation
Electron impact
Describe electrospray ionisation
The sample is dissolved in a volatile solvent and forced through a hypodermic needle that is connected to the positive terminal of a high voltage supply. As the droplets leave, the atoms each gain a proton. (Remember to subtract later)
What is an electron gun
A hot wire filament with a current running through it which emits a beam of high energy electrons which knock off an electron from each atom
What are the conditions in a mass spectrometer?
Vacuum so ions don’t collide with air molecules
