41. An atom, of carbon contains 6, protons and 6, neutrons, its mass, number, will be?
(a) 12,
(b) 6,
(c) 18,
(d) 24,
answer
(a) 12,
42. The “centre or core” of an atom, is called?
(a) Orbital,
(b) Nucleus,
(c) Proton,
(d) neutron,
answer
(b) Nucleus,
43. An element, has seven electrons, in its valance shell. Its valency, is?
(a) 7,
(b) 0,
(c) 1,
(d) 8,
answer
(c) 1,
44. Atom is “electrically”?
(a) Neutral ,
(b) Negative ,
(c) Positive ,
(d) all ,
answer
(a) Neutral ,
45. Atomic number, is denoted, by?
(a) Z,
(b) N,
(c) a,
(d) c,
answer
(a) Z,
46.” Atoms are composed ,of particles”?
(a) 2
(b) 4
(c) 5
(d) 3
answer
(d) 3
47. during a, physical change, the chemical ,composition of the, substance?
(a) Change
(b) Permanently change
(c) Does not change
(d) Temporarily change
answer
(c) Does not change
48. “Hydrocarbons” are the compound, of carbon and?
(a) Hydrogen
(b)Oxygen
(c) Nitrogen
(d) Chlorine
answer
(a) Hydrogen
49. “Polythene” is a?
(a) Monomer
(b) Polymer
(c) Element
(d) Fertilizer
answer
(b) Polymer
50.The products of “burning hydrocarbons” are?
(a) Carbon dioxide and water
(b) Oxygen & water
(c) Carbon dioxide and oxygen
(d) oxygen & nitrogen
answer
(a) Carbon dioxide and water
