2.2 Atoms, Ions And Compounds Flashcards
Atomic Number
Number of protons in the nucleus of an atom.
Mass Number
Number of protons and neutrons in nucleus that form mass of an atom.
Electron
Subatomic particle with charge of -1 and mass of 1/1836 that occupies shells around nucleus.
Proton
Subatomic particle with charge of +1 and mass of 1 found in nucleus of an atom.
Neutron
Subatomic particle with charge of 0 and mass of 1 found in nucleus of an atom.
Ion
A charged atom where number of electrons is different from number of protons.
Isotope
Atom with same number of protons and electrons but different number of neutrons in the nucleus.
Relative Atomic Mass
Weighted mean mass of an atom of an element compared to 1/12 mass of carbon-12.
Relative Isotopic Mass
Weighted mass of an atom of an isotope when compared to that of 1/12 of an atom of carbon-12.
Formula of relative atomic mass
(% abundance x mass)+(%abundance x mass) /100
Cation
Atoms with fewer electrons than protons. Have an overall positive charge.
Anion
Atoms with more electrons than protons. Have an overall negative charge
Uses of mass spectrometer
-Monitoring breath of patients during surgery.
-Detecting banned substances in athletics.
-Analysing molecules in space.
How do mass spectrometers works
1) Sample placed in mass spectrometer.
2) Vaporised then ionised.
3) Ions are accelerated by electromagnetic plate.
4) Ions are detected with (m/z)mass to charge ratio. Larger abundance= larger the signal.
Ionisation in mass spectrometer.
Electron from electron gun knocks electron from substance,producing a cation.
M+e = M+ + 2e-
Acceleration in mass spectrometer
Negative plate attracts positive ion making the ion accelerate to bend round corner.
Deflection in mass spectrometer
Uses magnetic field. Higher the mass= stronger magnetic field needed to reach the detector.
