Atomic structure Flashcards
Isotopes
Atoms of the same element which have different numbers of neutrons
Mass of protons, neutrons and electrons
1,1, 1/1800
Charge of proton, neutron and electron
+1, 0, -1
Atomic number
The number of protons in an element. All isotopes of an element have the same atomic mass. They are specific to each element.
Building an atom
Nearly all of the atoms mass is in the nucleus. Atoms with no charge have the same number of protons and electrons.
Mass number
Number of protons and neutrons
Positive ions
Are cations, they are atoms with fewer electrons then protons.
Negative ions
Are anions, they are atoms with more electrons then protons
Relative isotopic mass
The mass of an isotope relative to one twelfth of the mass of carbon-12
Relative atomic mass
The weighted mean mass of an atom of an element relative to one twelfth of the mass of an atom of carbon-12
Relative molecular mass
The ratio of the average mass of one molecule of an element or compound to one twelfth of the mass of an atom of carbon-12.
Relative formula mass
The sum of the relative atomic masses of the elements present in a formula
What can a mass spec be used to find out?
The percentage abundance of the isotopes in a sample of an element
What happens in mass spec
The sample is vaporised and ionised to form a positive ion. The ions are accelerated, heavier ions are slower so this is how the isotopes are separated. The ions are detected on a mass spec as a mass-to-charge ratio m/z.
Mass-to-charge ratio m/z
Relative charge on ion
