Periodic Classification of Elements
Points to Remember
Modern periodic law states that, the physical and chemical properties of the elements are the periodic functions of their atomic numbers.
The table in which elements are arranged in rows and columns in regular gradation is called periodic table.
Smelting is the process of reducing the roasted metallic oxide into metal in molten condition.
Dilute or con. HNO3 does not attack aluminium metal ,as it renders aluminium passive due to oxide film formation on its surface.
The charge used in the metallurgy of iron consists of roasted ore, coke and limestone in the ratio, 8:4:1.
Copper vessel on exposure to air and moisture forms a green layer on its surface due to basic copper carbonate.
An alloy is a homogeneous mixture of two or more metals.
An amalgam is an alloy of mercury with another metal. E.g. Ag-Sn amalgam is used for dental filling.
The chemical name of rust is hydrated ferric oxide and its formula is Fe2O3.xH2O.