TOPPER’S COACHING CENTRE
SCIENCE
BELGAUM
Class -VIII
CH- 4
Material:- Metals And Non-Metals
All materials are generally categorised into three categories1. Metals
Ex-iron, silver, gold, tin, copper ,aluminium, etc.
2. Non-metals Ex-carbon, sulphur ,nitrogen ,oxygen , bromine etc.
3. Semi-metal. Ex- silicon, germanium etc.
PHYSICAL PROPERTIES OF METALS1. They are shiny in nature.
2. They produce ringing sound after beating. This property of metal is
called as sonorous property.
3. They are found in solid state except mercury which exist as liquid.
4. They are hard.
5. They have high density.
6. They have high melting and boiling point.
7. They can be converted into sheets .this property of metal is called as
malleability. Gold and silver are most malleable metals.
8. They can be converted into thin wires .this property of metal is called
as ductility. Gold and silver are most ductile metals.
9. They are good conductor of heat and electricity.
PHYSICAL PROPERTIES OF NON-METALS1.They are not shiny.
2They are not sonorous.
3.They are found in all three states.
4.They have low density.
5.They have low melting and boiling point.
6.They are neither malleable nor ductile.
7.They are poor conductors of heat and electricity.
CHEMICAL PROPERTIES OF METALS
1.reaction with oxygenMetals +oxygen ------- metal oxide.
Ex- magnesium + oxygen -------heat----- magnesium oxide.
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TOPPER’S COACHING CENTRE
TCC
2. reaction of metal oxide with waterMetal oxide + water ---------base (metal hydroxide)
Ex-magnesium oxide + water -------- magnesium hydroxide
3.reaction of metal with acidMetal + acid ---------salt + hydrogen.
Ex- magnesium +hydrochloric acid ---------- magnesium chloride + hydrogen
CHEMICAL PROPERTIES OF NON-METALS
1.Reaction with oxygennon-metal +oxygen ---------- non-metal oxide
Ex- carbon + oxygen -------- carbon dioxide.
2.reaction of non-metallic oxide with waternon-metallic oxide + water--------- acid.
Ex- carbon dioxide + water--------- carbonic acid.
DISPLACEMENT REACTIONThe reaction in which more reactive element replaces less reactive
element.
Ex-zn + cuso4------------ znso4 + cu.
Reactivity seriesK-potassium
Na -sodium
Ca-calcium
Mg-magnesium
Al-aluminium
Zn-zinc
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TOPPER’S COACHING CENTRE
TCC
Fe-iron
Pb-lead
H-hydrogen
Cu-copper
Hg-mercury
Ag-silver
Au-gold
reactivity decreases down the series.
Acidic oxides: The oxide of non-metals are acidic oxides as they dissolve
water to give acids.
Basic oxides: The oxides of metal the basics in nature as they form bases
on addition of water.
Q1) name the most ductile metal?
Ans) Gold.
Q2) Name the metal that exist in liquid state?
Ans) Mercury.
Q3Which non-metal is good conductor of electricity?
Ans) Graphite
Q4) Which metal is constituent of haemoglobin?
Ans) Iron
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