LONG ANSWER QUESTIONS:
Q1) discuss the main physical and chemical properties of non-metals?
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Science ch-4 Materials:Metals and non-metals. it's really urgent.
Answers
Answer:
Elements that tend to gain electrons to form anions during chemical reactions are called non-metals. These are electronegative elements with high ionization energies. They are non-lustrous, brittle and poor conductors of heat and electricity (except graphite).
Explanation:
Metals Non-metals
Good conductors of electricity Poor conductors of electricity
Good conductors of heat Poor conductors of heat
High density Low density
Malleable and ductile Brittle
Explanation:
Non-Metal are those elements which do not exhibit the metallic characteristics. In the periodic table non-metals are kept almost in the right most. In modern periodic table there are 22 non-metals in which there are 11 gases, 1 liquid and 10 solid. Bromine occurs in the state of liquid and hydrogen, nitrogen, oxygen, chlorine etc are found in gaseous forms. But carbon, sulphur, phosphorous, iodine etc solid non-metals.
Physical properties of non-metal :
The physical properties of non-metal are given below:
• They do not produce metallic lustre.
• They are bad conductor of electricity.
• They are bad conductor of heat.
• They are electronegative.
• They cannot be drawn into sheets and wires.
• They have low specific gravity.
• They do not reflect light.
• They do not produce metallic sound.
• They are found in all states of matter.
Chemical properties of non-metal :
The chemical properties of non-metal are given below:
• Non metallic oxides are acidic in nature.
• They do not dissolve in dilute mineral acids.
• They form stable compound with hydrogen.
Their chlorides are completely hydrolyzed by water.
• Reaction of non-metals with oxygen:
They react with oxygen to form acidic oxides or neutral oxides.
• Reaction of non-metals with water:
They do not react with water (steam) to evolve hydrogen gas.
• Reaction of non-metal with acids:
They do not react with acids because they are negative charged electron.
• Reaction of non-metal with salt solution: They do not react with salt solution but displaces less reactive non-metal from the salt.
• Reaction of non-metal with chlorine:
They are react with chlorine to form covalent chlorides which are non- electrolytes.
