Subject: Metals and non methals
Alcaline Earth metals and halogens
Introduction
Earliest classification of elements was on the basis of their appearance and physical or chemical properties. That time
few elements were known therefore it was quite easy to classify those elements on the basis of their properties.
According to that concept, elements can be classified as metals and non-metals. Both of these types of elements are
differed in their appearance, reactivity, conductivity and chemical properties. For example, metals have a lustre surface
with electropositive nature. They have 1, 2, or 3 electrons in their valence therefore metals tend to lose electrons to
form cations. That is the reason; they are a good conductor of heat and electricity.
Metals are hard, malleable and ductile in nature. Because of the formation of cation, they form ionic compounds with
non-metals. On the contrary, non-metals are brittle solids or liquids and gases. They are electronegative in nature as
they tend to accept electrons and form anions. These anions can form ionic compounds with metals such as sodium
chloride. Today in the long form of the periodic table, non-metals are placed at the right side of the table from 13th to
18th group. Let’s discuss the position of different non-metals in the periodic table with their characteristics Metals are
very reactive. They tend to loose electrons easily and form positively charged ions; therefore metals are called
electropositive elements. Sodium metal forms sodium ions Na + , Mg forms positively charged Magnesium ions
Mg 2+ and aluminium forms aluminium ions Al 3+ . The electropositive nature allows metals to form compounds with
other elements easily.
Metals Non-metals
Shiny surface, has characteristic luster. Not lustrous at all. Most of them are dull elements.
Good conductor of electricity. Poor conductor of electricity, due to the lack of metallic
bond.
Metals are solids, except mercury, the only liquid metal. Non-metals are solids, liquids and gases.
Metals on reaction with non-metals, lose electron(s) to form a Non-metals gain electron(s) from the metals, to form
positive ion or cation.
negative ion or anion.
Non-metals form ionic, covalent and coordinate bonds
too.
Metals only form ionic compounds.
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