CONCEPT NOTES
Elements are classified into two basic categories, metals and non-metals
Before giving the definition of metal and non-metal, we must know some important terms:
(i) Malleability: Ability of an element due to which it can be beaten with hammer into thin sheets.
(ii) Ductility: Ability of an element due to which it can be drawn into wires.
(iii) Sonorous: Property of an element to produce sound when it is struck with a hard substance
(iv) Brittleness: Property of an element to break easily into pieces on hammering or stretching
MCQ TEST
- Which of the following metals is present in the anode mud during the electrolytic refining of copper?
(a) Sodium
(b) Aluminium
(c) Gold
(d) Iron
2. An element reacts with oxygen to give a compound with a high melting point. The compound is soluble in water. The element is likely to be
(a) calcium
(b) carbon
(c) iron
(d) silicon
3. The second most abundant metal in the earth’s crust is
(a) oxygen
(b) silicon
(c) aluminium
(d) iron
4. An alloy of Zn and Cu is dissolved in dil. HC1. Hydrogen gas is evolved. In this evolution of gas
(a) only zinc reacts with dil. HC1
(b) only copper reacts with dil. HC1
(c) both zinc and copper react with dil. HC1
(d) only copper reacts with water
5. A greenish coating develops on copper utensils due to formation of
(a) CuCo3
(b) Cu(OH)2
(c) Cu(OH)2.CuCO3
(d) CuO
6. Rusting of iron takes place in
(a) ordinary water
(b) distilled water
(c) both ordinary and distilled water (d) none of the above
7. The bronze medals are made up of
(a) Cu and Zn
(b) Zn and Ni
(c) Cu and Sn
(d) Cu, Zn, Tn
8. Silver articles become black on prolonged exposure to air. This is due to the formation of
(a) Ag2O
(b) Ag2S
(c) AgCN
(d) Ag2O and Ag2S
9. During smelting, an additional substance is added which combines with impurities to form a fusible product known as
(a) slag
(b) mud
(c) gangue
(d) flux
10. A student placed an iron nail in copper sulphate solution. He observed the reddish brown coating on the iron nail which is
(a) soft and dull
(b) hard and flading
(c) smooth and shining
(d) rough and granular
ANSWERS