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Elements of Life:
Protons 1 +1
Neutrons 1 0
Electrons Negligible -1
Atoms are made up of fast moving electrons moving around a positive nucleus made if protons
Absorption and emission spectra:
Emission spectra are coloured lines on a black background.
Process: 1) Electrons get excited and move up energy levels
2) Electrons drop to ground state and emit photon of light
3) This photon's frequency is equivalent to the levels Dropped.
Absorption spectra are black lines on a coloured background.
Process: 1) Electrons absorb a photon of light of specific frequency
2) They become excited and move up energy levels
3) Height moved is equivalent to the frequency of light absorbed.
Some nuclei are unstable and so randomly emit radioactive particles.
What is it Charge Stopped by Deflection in electric field
Alpha Helium Nucleus +2 Paper Low
Beta Electron -1 Aluminium foil high
Gamma Electromagnetic 0 Thick lead None
The half-life is the time taken for the radioactive activity of a nucleus to halve. This is a constant for
any specific isotope of an element. Radioactive decay is random.
Nuclear Fusion is when lighter atoms join to create heavier atoms under high temp and pressure.
Radioactive isotopes are used as tracers, tracer selection depends on half-life and length required.
Molecules and their shapes:
Atomic Number: number of protons
Mass Number: number of protons and neutrons
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Isotopes: atoms with the same atomic number but different mass number
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Reactions with water increase as you go down the group. The basicity increases down the group.
Carbonates are thermally more stable down the group. Hydroxides are more soluble down the
group. Carbonates are less Soluble down the group.…read more