Metals and Non-Metals


– Ionization energy of an atom is the amount of energy needed to remove an electron from itself.

– Electronegativity of an atom refers to its tendency to attract electrons.

– Electron affinity of an atom refers to the amount of energy given out when an electron is added to a neutral atom to form a anion.

– All three ionization energy, electronegativity and electron affinity of an atom decrease down a group but increase across a period. The higher the ionization energy, electronegativity and electron affinity, the more non-metallic characteristics an atom has. The opposite also holds true that with lower ionization energy, electronegativity and electron affinity, the more metallic characteristics an atom would have.

– Some differences between metals and non-metals are shown in the table below:

MetalsNon-metals
Usually strong and hard,ductile and malleableUsually weak and soft and cannot be bent,
stretched or drawn into wires
Generally have high melting and boiling points
(with the exception of Group I metals)
Generally have low melting and boiling points
(with the exception of boron, carbon and silicon)
 Usually solids at room temperature
(with the exception of mercury)
 Usually gases at room temperature
(with the exception of boron, carbon,
silicon, phosphorus, sulphur, bromine and iodine)
 Good conductors of heat Poor conductors of heat
 Good conductors of electricity Poor conductors of electricity
(with the exception of carbon or graphite)
 Always form cations Usually form anions
 Usually forms ionic bonds Usually forms covalent bonds
 Forms basic or amphoteric oxides Forms neutral or acidic oxides

– Amphoteric oxides of metals have some of both acidic and basic properties. (See: Acids, Bases and Salts)


 

Transition Metals 

– Are a group of metals in the middle of the Periodic Table

– Have the following physical and chemical properties:

  • Very high melting and boiling points
  • Very high densities
  • Variable number of valence electrons –> can have different oxidation states eg. $Cu^{+}$, $Cu^{2+}$, $Fe^{2+}$, $Fe^{3+}$
  • Form coloured compounds
    eg. $Cr^{2+}$, $Cu^{2+}$ and $V^{4+}$ form blue compounds,
    $Cr^{3+}$, $Fe^{2+}$, $Mn^{6+}$, $Ni^{2+}$ and $V{3+}$ form green compounds,
    $Co^{2+}$ and $Mn^{2+}$ form pink compounds,
    $Co^{3+}$, $CrO_{4}^{2-}$ and $Fe^{3+}$ form yellow compounds
    $Cr_{2}O_{7}^{2-}$ forms orange compounds and
    $Mn^{7+}$ forms violet compounds
  • Not as reactive as metals in Group I and Group II
  • Are good catalysts

– Uses of transition metals:

Transition MetalsUses
IronAs a catalyst in the Haber Process to
manufacture ammonia gas
NickelAs a catalyst in the manufacturing of magarine
VanadiumAs a catalyst in the Contact Process to
manufacture sulphuric acid
TitaniumIn aircraft construction, making spectacle frames
and watches due to its non-corrosive and
strong yet light properties
TungstenFilament for light bulbs because it is
ductile and has high melting points

 

Next: Group I, Group VII and Group O Elements

Previous: The Periodic Law

Back to The Periodic Table


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