Forum

Structure Of The Atoms

Rutherford’s α–particle scattering experiment showed that
(i) electrons have negative charge
(ii) the mass and positive charge of the atom is concentrated in the nucleus
(iii) neutron 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)

05/11/2024

Science

9th

Structure Of The Atoms

In the Thomson’s model of atom, which of the following statments are correct?
(i) the mass of the atom is assumed to be uniformaly distributed over the atom
(ii) the positive charge is assumed to be uniformaly distributed over the atom
(iii) the electrons are uniformaly distributed in the positively charged sphere
(iv) the electrons attract each other to stabilise the atom
(a) (i), (ii) and (iii)
(b) (i) and (iii)
(c) (i) and (iv)
(d) (i), (iii) and (iv)

05/11/2024

Science

9th

Structure Of The Atoms

Which of the following are true for an element?
(i) Atomic number = number of protons + number of electrons
(ii) Mass number = number of protons + number of neutrons
(iii) Atomic mass = number of protons = number of neutrons
(iv) Atomic number = number of protons = number of electrons
(a) (i) and (ii)
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (ii) and (iv)

05/11/2024

Science

9th

Structure Of The Atoms

Which of the following statements about Rutherford’s model of atom are
correct?
(i) considered the nucleus as positively charged
(ii) established that the α–particles are four times as heavy as a hydrogen
atom
(iii) can be compared to solar system
(iv) was in agreement with Thomson’s model
(a) (i) and (iii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) only (i)

05/11/2024

Science

9th

Structure Of The Atoms

Dalton’s atomic theory successfully explained
(i) Law of conservation of mass
(ii) Law of constant composition
(iii) Law of radioactivity
(iv) Law of multiple proportion
(a) (i), (ii) and (iii)
(b) (i), (iii) and (iv)
(c) (ii), (iii) and (iv)
(d) (i), (ii) and (iv)

05/11/2024

Science

9th

Structure Of The Atoms

Rutherford’s ‘alpha (α) particles scattering experiment’ resulted in to
discovery of
(a) Electron
(b) Proton
(c) Nucleus in the atom
(d) Atomic mass

05/11/2024

Science

9th

Structure Of The Atoms

Which of the following correctly represent the electronic distribution in the
Mg atom?
(a) 3, 8, 1
(b) 2, 8, 2
(c) 1, 8, 3
(d) 8, 2, 2

05/11/2024

Science

9th

Atoms & Molecules

A silver ornament of mass ‘m’ gram is polished with gold equivalent to 1%
of the mass of silver. Compute the ratio of the number of atoms of gold and
silver in the ornament.

05/11/2024

Science

9th

Atoms & Molecules

What are ionic and molecular compounds? Give examples.

05/11/2024

Science

9th

Atoms & Molecules

A gold sample contains 90% of gold and the rest copper. How many atoms
of gold are present in one gram of this sample of gold?

05/11/2024

Science

9th