Physical - 1.1 Atomic Structure Flashcards
What happens in acceleration (TOF)?
The second stage of TOF spectrometry. The positively charged ions are accelerated by an electric field so that they have the same kinetic energy.
What is the atomic nucleus?
Positively charged object composed of protons and neutrons at the centre of every atom with electrons orbiting it.
Define atomic number
The number of protons in the nucleus.
What is electron impact ionisation?
Method of ionisation in TOF spectrometry. The sample is vapourised and an electron gun fires high energy electrons at it, causing an election to be knocked off each particle to produce 1+ ions.
What is electrospray ionisation?
Method of ionisation in TOF spectrometry. The sample is dissolved and pushed through a fine nozzle at a high pressure. A high voltage is applied to it causing each particle to gain an H+ ion. The sample is then turned into a gas.
Define first ionisation energy
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions.
Define isotope
Atoms of the same element with the same number of protons but a different number of neutrons.
Define mass number
The total number of protons and neutrons in the nucleus.
Define second ionisation energy
The energy required to remove 1 mole of electrons from 1 mole of gaseous 1+ ions to form 1 mole of gaseous 2+ ions.
What is a TOF spectrometer?
A method of mass spectrometry where an ions m/z ratio is determined by a time of flight measurement. Consists of four stages: ionisation, acceleration, in drift, and detection.
What is an electron configuration?
The distribution of electrons of an atom in orbitals.
What happens in ion detection?
Fourth stage of TOF spectrometry. The negatively charged plate detect charged particles and a mass spectrum is produced.
What happens in ion drift?
The third stage of TOF spectrometry. The ions enter region with no electric field so they drift through it. The light of the ion, the faster they will drift.
What happens in ionisation (TOF)
First stage of TOF. The sample can be ionised by electro spray ionisation or electron impact ionisation.
What did the plum pudding model represent?
It represented atoms as a sphere of positive charge, with small negative charges distributed evenly within it
What is the electron shell model (Rutherford)?
The atom consists of a small, dense central nucleus surrounded by orbiting electrons in electron shells
What is the relative charge and mass of a proton?
Relative charge = +1
Relative mass = 1
What is the relative charge and mass of a neutron?
Relative charge = 0
Relative mass = 1
What is the relative charge and mass of an electron?
Relative charge = -1
Relative mass = 1/1840
What is the mass number a sum of?
The sum of protons and neutrons in an atom
What is atomic number equal to?
The number of protons
What happens in ionisation (TOF)?
A sample of an element is vaporised and injected into the mass spectrometer where a high voltage is passed over the chamber. This causes electrons to be removed from the atoms leaving +1 charged ions in the chamber.
What happens in acceleration (TOF)?
These positively charged ions are then accelerated towards a negatively charged detection plate
What happens in acceleration (TOF)?
These positively charged ions are then accelerated towards a negatively charged detection plate