Topic 1: Atomic Structure & The Periodic Table Flashcards
What is the definition of relative atomic mass ?
The weighted mean mass of an atom of an element relative to the 1/12th the mass of a carbon-12 atom
What are isotopes
Atoms of the same element with the same number of protons but a different number of neutrons
What has to be done in order to calculate the relative atomic mass?
Chemical analysis (mass spectrometry) is carried out.
Gives us info on the relative abundance of each isotope in the sample
Molecular mass of CO2
12.0 + (16.0 x 2) = 44.0
What does a mass spectrometer measure
The masses of atoms and molecules (as well as the fragments that make the molecule up)
On a mass spectrometry graph how do we calculate relative atomic mass when y axis is %
(Mass x abundance)+(mass x abundance)
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100
On a mass spectrometry graph how do we calculate relative atomic mass when y axis is relative abundance instead of percentage abundance?
(Mass x abundance) + (mass x abundance)
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Sum of isotopic abundances (peaks on graph)
what does the molecular ion peak (peak furthest to the right) tell us ?
Relative molecular mass
What are the 4 stages of mass spectrometry
Ionisation
Acceleration
Deflection
Detection
Why must the ionisation chamber in mass spectrometry be a vacuum?
If there were any loose gas particles they would be ionised and picked up on the detector which would interfere with results
What is important about the sample in mass spectrometry
The sample must be vaporised so that all particles are in a GASEOUS state
Describe how ionisation works in a mass spectrometer
Sample is inserted and bombarded with a beam of high energy electrons.
Electrons are knocked off- creates positive ions
Why must the sample be ionised (mass spectrometry)
Must be positive ions in order to get detected
How are the ions accelerated (mass spectrometry)
Electric field helps accelerate the ions
What helps deflection (mass spectrometry)
Magnetic field created by an electromagnet - bends the path of ions
What can you find out from position of detection? (Mass spectrometry)
The larger the mass of the ions, the less they are deflected and the position of detection depends on amount of deflection
What is the order of how shells are filled
1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 4d, 4f
What do the coefficient, the letter and the power represent eg. 3s^2
3 - quantum shell
s- type of orbital
2- number of electrons
What is the maximum amount of electrons an s-orbital can hold
2
What is the maximum amount of electrons a p-orbital can hold?
6
What is the maximum amount of electrons a d-orbital can hold?
10
What is the maximum amount of electrons an f-orbital can hold?
14
What is the shape of an s-orbital
Spherical