Atomic and electronic structure 3
- Created by: hudaa
- Created on: 23-11-13 14:01
atomic number & mass number -all atoms are made up of protons, electrons and neutrons-nuetral atoms have same electron and protons number-mass of atom is the nos of proton and neutron together-protons has + charge electrons has -- charge neutrins have no charge the atomic number of an atom is the number or protons in its nucleas- Z the mass number of an atom is the number or protons and neutrons together(nucleon no.) -A comparing the masses of atoms - mass spectrometry uses of mass spectrometry:-seperates atoms and molecules according to there mass.-shows the relative number of diffrent atoms and molecules.-isotopic composition of elements. conditions: -atoms must be converted into positive ions- ions should be in gaseous state stages in mass spectrometer: 1- vaporisation: inject the chemical to be tested into the instrument, high vaccum will cause the chemical to vaporise.2- ionisation: bombard the sample woth high-energy electrons, these will knock out the electrons in the sample forming positive ions:e- + X ---> X+ + e- + e- 3- acceleration: electric field is used to accelerate those positive ions.4-deflection: deflect those moving ions by a magnetic feild, lighter ions are deflected more than heavier ones.5- detection: detect the charged ion as a tiny current by using a reference compound with known structure and relative molecular mass. on the spectrum diffrent peaks will occur each will…
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