Atomic Structure Flashcards
Define element
A type of atom with the same number of protons
What is the charge and mass of a proton, electron and neutron?
Proton: Charge of +1, mass of 1
Electron: Charge of -1, mass of 1/2000
Neutron: Charge of 0, mass of 1
Define ion
A charged atom which has gained or lost electrons
Define mass number
Number of protons plus the number of neutrons in the nucleus
Define atomic number
Number of protons
Define isotopes
Atoms of the same element which have different numbers of neutrons in it’s nucleus
Define relative isotopic mass
Mass of an individual atom of a particular isotope relative to 1/12 of carbon-12
Define relative atomic mass
Weighted mean mass of an atom of an element compared to 1/12 of the mass of carbon-12
How do you work out the RMM of a molecule?
- Multiply the mass number of each element in the compound by the small number and add them all together
- The unit is generally g/mol
What instrument proved the existence of isotopes?
Mass Spectrometer
What are the basic points of a mass spectrometer?
1- Vaporisation
2- Ionisation by an electric gun (always positive charge)
3- Acceleration and focus by an electric field
4- Deflection by a magnetic field, the higher the charge the more it is deflected
5- Detection by the ion counter
On a mass spectra, what does the height of the peak show?
The abundance of the particular isotope
How do you calculate the relative atomic mass of an element from a mass spectra?
(abundance of peak 1 X mass of peak 1) + (abundance of peak 2 X
Give an equation to show how chlorine molecules (Cl2) ionise in a mass spectrometer
Cl2 + e- = Cl2+ + 2e-
How do you find the relative molecular mass of a molecule on a mass spectra?
Look for the peak with the highest mass
