Atomic Structure Flashcards
Define Nucleus
Most of the mass of an atom and very small. Contains protons and neutrons
Define electrons
Orbit the nucleus in shells and take most of the space of an atom.
Proton relative charge
+1
Proton relative mass
1
Neutron relative charge
0
Neutron relative mass
1
Electron relative charge
-1
Electron relative mass
1/1840
Mass number
number of protons and neutrons in the nucleus
Atomic number
Protons in the nucleus
Define ion
Different number of electrons and protons
Negatively charged ions
Gained an electron
Positively charged ions
Lost an electron to form a full shell
Define isotopes
Elements with the same proton number but a different number of neutrons
Define relative atomic mass
the weighted mean mass of an atom of an element, compared to 1/12th of the mass of an atom of carbon-12
Define relative molecular mass
mean mass of a molecule, compared to 1/12th of the mass of an atom of carbon-12
Relative isotopic mass
the mass of an atom of an isotope, compared to 1/12th of the mass of an atom of carbon-12
What axis is the abundance on?
y
What is abundance shown as
%
What is m/z
the mass of an isotope divided by charge. As most have just a + charge this is the same as the isotopic mass.
How to find relative atomic mass (mass spectra)
Relative atomic mass = (abundance A X m/z A) + (Abundance B X m/z B)
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Total abundance
Stages of predicting mass spectra
1) Write the percentages as decimals
2) Create a table showing the isotope combinations in a molecule of whatever your dealing with. Multiply the decimal from abundances of each isotope to get the relative abundance for each molecule.
3) Any molecules which are the same add the abundances up
4) . Divide all the relative abundances worked out before by the smallest value. This will give you a whole number ratio which can be used to predict your spectra.
Mass spectra- molecules
What do peaks show?
What is the significance of the M+
Fragments of the original molecules
The M+ peaks is the last peak or the molecular ion peak, which is the same as the relative molecular mass of the molecule
Mass spectra- molecules
What is the m/z meaning
m/z is just the mass of a fragment divided by charge. As most have just a +1 charge this is the same as the fragment mass.
Electron configuration- subshells
Electron shells are split into 4 subshells
S Subshell
Orbital number + how many electrons can they hold?
s – has 1 orbital can hold 2 electrons