Dalton's atomic structure (1808)

• All matter consists of atoms

• Elements consist of atoms

• Compound consist of atoms of more than one element

• In a reaction atoms are not created nor destroyed

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Thomson's model (1906)

• "Plum pudding" model

Rutherford's gold foil experiment

• ​Proved the empty space in an atom

Sub atomic particles

• Proton

• Neutron

• Electron

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Nuclear symbol

A: number of protons + neutrons

Z: number of protons

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Mass spectrometer

• Used to determine the Relative atomic mass of an element

• 5 Stages: Vaporization-->ionization--> acceleration-->deflection-->detection

Tip: You only need to know the order of the stages, not how each stage works.

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Radio isotopes​​

• medical chemistry

  • Iodine 131 to obtain image of tyre​oid gland

  • iodine 125 to treat cancer and tumors

  • Cobalt 60 in radiotherapy

• Dating​

  • Carbon 14 in cosmic, geological and archeological dating​

    • Half-Life: time it takes for an amount of radioactive  isotopes to decrease to one half of its initial value​

    • Example: carbon half-life: 5730 years

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Emission Spectra

• A pure gaseous element subjected to a high voltage and reduced pressure will emit a certain wave length.

• Quantisation energy:

  • formula:

• When the electron falls back from the excited state to the ground state it emits a photon, a discrete amount of energy.

• Hydrogen line emission spectrum

• ​Series

• At the limit of convergence of the spectra there is a continuum. Beyond this energy there is a free electron.

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Orbitals (Quantum mechanical model)

• Region in space where there is a high probability of finding an electron

• each orbital can hold a maximum of 2 electrons

• s orbital is spherically symmetrical

• p orbital is dumbbell shaped. There are 3 atomic orbitals,               each in one cartesian axes​

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  • Orbital diagram:

    • Example:​ Zn

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  • ​​​​Condensed configuration:

    • ​​Example:​​

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• Configurations​​

  • Full electron configuration:​

    • Example​: