Metals and Non-Metals with Physical and Chemical Differencess

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Elements in the periodic table are classified mainly as metals and non-metals. In early days, metals were identified from non-metals by their physical characteristics. Some of the physical characteristics of metals and non- metals are given below.

Physical Differences Between Metals and Non-Metals:

Metals:

1. All metals except mercury are solids with high melting points and boiling points.
2. Metals have characteristic lusture, known as metallic lusture and can be polished.
   
3. They on hitting with hammer give off notes i.e. they are Sonorous.
4. Metals are malleable and ductile that is they can be converted into sheets and wires.
5. Metals have great tensile strength and can withstand stress and strain. They have relatively high densities.
6. They have relatively high densities.
7. They are good conductors of heat and electricity. Some common metals are iron (Fe), Copper (Cu), Aluminum (Al) and Chromium (Cr).

Non-Metals:

1. Non-metals have low melting and boiling points, about half of non-metals are gases.
2. Non-metals do not have lusture like metals and can not be polished.
3. They are not sonorous and break on hitting.
   
4. They are usually brittle and break easily when subjected to stress or strain.
   
5. They are neither malleable nor ductile.
6. They are generally bad conductors of heat and electricity.
7. They have relatively low densities. Some examples of non-metals are Sulphur(s), Carbon(C), Oxygen(O2), Nitrogen(N2) and Chlorine(Cl2).

Chemical Differences Between Metals and Non-Metals:

Metals and non-metals not only differ in their physical properties but also show characteristic differencess in their chemical properties. The Common differences are in their oxides formations.

Metals combine with oxygen on burning to yield basic oxides i.e. the oxides of metals are basic in character. When dissolved in water they form alkaline solution that turns red litmus blue. On the other hand, non-metals combine with oxygen on burning to yield acidic oxides i.e. the oxides of non-metals are acidic in character. When dissolved in water they form acidic solutions that turn blue litmus red.
Metals have few electrons in their valence shells so have greater tendency to lose electrons during chemical reactions to form electrovalent i.e. ionic compounds and are electropositive elements to produce positive ions i.e. cations.

For Example:


(2,8,1) .(2,8)



(2,8,2) ..(2,8)


(2,8,3) ....(2,8)

On the other hand non-metals have more electrons in their valence shells, usually four to seven electrons in their valence shells. So they have either the tendency to accept or gain electrons in chemical reactions to form ionic or electrovalent compounds and form negative ions i.e. anions. Or they share electrons during chemical reactions to form covalent compounds. The number of electrons gained per atom of non-metal is the valency of the non-metal.

For Example:


(2,8,7) ...................(2,8,8)


(2,8,6) .................(2,8,8)

The important differences in the chemical properties of metals and non-metals are due to their ability to lose or gain or share electrons respectively.