C1. Atomic Structure Flashcards
Who proposed the idea of elements and substances that could not be made simpler?
Robert Boyle 1661
Who proposed the idea that elements were composed of indivisible atoms, atoms of particular elements had same mass ?
John Dalton 1803
Who proposed the idea that electrons were located within the atom in circular arrays , plum pudding model
J.J Thomson 1896
Who proposed the idea that the mass and positive charge of the atom was in a tiny central nucleus?
Ernest Rutherford and his team 1911
What are the 3 fundamental particles?
Protons, Neutrons and electrons
What are nucleons?
Name given to the Protons and neutrons as they are found in the nucleus
Whats the relative charge and mass of Neutrons?
1 relative mass, 0 relative charge
Whats the relative charge and mass of Electrons?
1/1840 relative mass, -1 relative charge
Whats the relative charge and mass of Protons?
Relative mass is 1, relative charge is +1
What force are the protons and neutrons held together by?
The strong nuclear force - Much stronger than electrostatic forces of attraction
What is the atomic number Z?
Number of protons
What is the mass number A?
Total number of protons and neutrons in the nucleus
What are isotopes?
Atoms with the same number of protons but different number of neutrons
How do you date organic matter using isotopes?
Living matter has fixed portion of Carbon-14, half life of 5730 years, once living material die the C-14 decays
Who proposed the idea that atoms consisted of tiny positive nucleus orbited by negatively charged electrons to form an atom?
Niels Bohr 1913
Who proposed the idea of electrons carrying wave like properties , leading to quantum mechanics?
Erwin Schröndinger 1926
Who proposed the idea of the neutron?
James Chadwick 1932
Whats the equation for Number of electrons in each shell?
2n² (n is number of shells)
What is the mass spectrometer used for?
Finding relative atomic mass
What is the definition of relative atomic mass?
(Average mass of 1 atom) / (1/12 mass of Carbon 12)
What is the definition of relative molecular mass?
(Average mass of 1 molecule) / (1/12 mass of Carbon 12)
What are the 6 stages of TOF mass spectrometer?
Vacuum, Ionisation, Acceleration, Ion drift, Detection, Data analysis
What occurs in vacuum of TOF?
High vacuum prevents collisions between ions that have been made and molecules in air
What occurs in Ionisation of TOF?
electrospray ionisation or Electron gun
What occurs in electrospray ionisation of TOF?
Sample dissolved in volatile solvent; positive droplets produced by injecting solution through needle to positive terminal - high voltage; particles lose electrons; Solvent evaporates leaving single positivity charged ions, Mr increases by 1
What occurs in electron gun stage of TOF?
Beam of high energy electrons knock electrons out of sample creating positively charged ions and free radicals; May cause fragmentation
What occurs in Acceleration of TOF?
Positive ions are accelerated by electrical field giving each ion same amount of kinetic energy; particles with lower mass / charge ratio experience greater acceleration ,they are lighter but given same amount of energy as heavier ions
What occurs in ion drift of TOF?
Beam of ions leave field with constant speed and kinetic energy; beam of particles moves into flight tube , no electrical field so particles can drift; ions with lower M/z ratios drift faster than those with larger M/z ratios
What occurs in detection of TOF?
Detector detects current generated as positively charged particles hit the plate , recording how long it took to drift through chamber; this is used to generate m/z values to produce mass spectrum; particles with lower m/w ratios reach detector first
What occurs in data analysis of TOF?
Detector sends signal to a computer to generate a mass spectrum
Whats the chemical equation for electron gun ionisation of X?
X(g) + e- = X+(g) + 2e-
Whats the difference between Electrospray ionisation and electron gun?
Electrospray ionisation results in proton gain, electron gun loses electron
What are the energy levels in orbitals?
s, p ,d ,f
What is the definition of an orbital?
Region with maximum probability of the electron
What is the Pauli exclusion principle?
Each orbital can contain a maximum of 2 electrons, 1 spin up 1 spin down
What are the amounts of electrons each orbital hold?
s 1 orbital = 2; p 3 orbitals = 6; d 5 orbitals = 10; f 7 orbitals = 14
What is the Aufban principle?
Electrons fill energy levels in order of increasing energy
What are the layout of orbitals?
1S;
2S 2P;
3S 3P 3D;
4S 4P 4D 4F;
What is Hund’s rule?
Electrons will occupy orbitals as single unpaired electrons all with same spin, then will pair up till no vacant orbitals in that sub levels
