Question

The major contribution in knowing the relative positions of electrons and protons in an

atom was given by Ernest Rutherford, a scientist from England. He performed the famous

alpha particles scattering experiment in the year 1911.For this he selected a thin foil of a

heavy gold metal. It was about 1000 atoms thick. He bombarded the same with high speed

alpha particles. These are in fact, positively charged helium nuclei. These were emitted

from a radioactive element radium enclosed in a lead box. These alpha particles were first

passed through a fine slit and then made to strike against the gold foil. To his surprise got

scattered and produced bright flashes on a circular screen coated with a substance called

zinc sulphide.

1. Rutherford’s alpha particles scattering experiment showed that

i) electrons have negative charge.

ii) the mass and positive charge of the atom is concentrated in the nucleus.

iii) neutrons exists in the nucleus.

iv) most of the space in atom is empty.

Which of the above statements are correct?

a) i and iii b) ii and iv c) i and iv d) iii and iv.

2. Rutherford selected a gold foil in his alpha ray experiment because

a) it is a light metal b) it is malleable .

c) it is ductile d) it is lustrous.

3. In Rutherford’s scattering experiment the number of alpha particles bounce back is

very small because

a) the gold foil is thin. b) the velocity of alpha particles is very large.

c) the volume of the nucleus is very small in comparison to the volume of the atom.

d) charge on nucleus is negative.

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Answer 1

Answer:

which.... the...following. has........

centre.........ymmetry

a).

HCL...

b.). Ha O.......

C). Erans N2f2......dHC.H.O.....

Explanation:

which.... the...following. has........

centre.........ymmetry

a).

HCL...

b.). Ha O.......

C). Erans N2f2......dHC.H.O.....