Structure of the Atoms Test

Result

Structure of the Atoms Test - 46

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

In a Bohr's model of an atom when an electron jumps from n=1 to n=3, how much energy will be emitted or absorbed in erg?

A
$$2.15\times { 10 }^{ -11 }$$

B
$$0.191\times { 10 }^{ -10 }$$

C
$$2.389\times { 10 }^{ -12 }$$

D
$$0.239\times { 10 }^{ -10 }$$

Solution
Question 2
1 / -0

Which of the following observations was not correct during Rutherford's scattering experiment?

A
Most of the $$\alpha$$-particles passed through the gold foil undeflected.

B
A small fraction of the $$\alpha$$-particles was deflected by small angles.

C
A large number of the $$\alpha$$-particles were bounced back.

D
A very few $$\alpha$$-particles (~1 in 12,000) were bounced back.

Solution

Very few bombarded $$\alpha$$-particles on gold foil were deflected by sharp angles and therefore, it was concluded that the positive charge is concentrated in a very small volume of the atom called nucleus.
Most of the particles passed through the foil undeflected and was concluded that most of the space in an atom is empty.
A very few $$\alpha$$-particles (approx. 1 in 12,000) were bounced back.
So option $$C$$ is only incorrect statement.
Question 3
1 / -0

Which of the following conclusions regarding the structure of the atom is based on Rutherford's $$\alpha$$-particle scattering experiment?

A
The positive charge is concentrated in a very small volume of the atom.

B
The positive charge is scattered with the electrons throughout the atom.

C
The volume occupied by the nucleus is half of the volume of atom.

D
Most of the space in the atom is occupied by the neutrons.

Solution

Very few bombarded $$\alpha$$-particles on gold foil were deflected by sharp angles and therefore, it was concluded that the positive charge is concentrated in a very small volume of the atom called a nucleus. Since few were deflected, the size of the nucleus is very small as compared with atom size.
option $$A$$ is correct.
Question 4
1 / -0

Which of the following properties of atom could be explained correctly by Thomson's model of atom?

A
Overall neutrality of atom

B
Spectra of hydrogen atom

C
Position of electrons, protons and neutrons in atom

D
Stability of atom

Solution

Hint: All atoms include tiny negatively charged subatomic particles or electrons, according to J.J. Thomson's work with cathode ray tubes.

Explanation:

According to the Thomson atom model:

1. An atom is spherical and has a radius of $$10^{-10}$$ meters.

2. The positive charge in the atom is evenly distributed.

3. The electrons are embedded in such a way that the atom's electrostatic configuration is the most stable.

As a result, the model was able to explain the atom's overall neutrality.

4. The atom's mass is considered to be evenly distributed across the atom.

It was unable to account for atomic spectra, atomic stability, or the real distribution of electrons, protons, and neutrons within the atom.

Final Answer:

The correct answer is option $$(A)$$.
Question 5
1 / -0

Radius of $$2nd$$ shell of $$He^+$$ (where $$a_0$$- Bohr radius)

A
$$3a_0$$

B
$$a_0$$

C
$$\dfrac{3}{2}a_0$$

D
$$2a_0$$

Solution

Radius of the Bohr's orbit is given by,
$$r=\dfrac{h^2n^2}{4\pi^2 m Z e^2}$$
Substituting values of h, m for helium ion and the electronic charge r may be calculated as
$$r=\dfrac{0.529n^2}{Z}A^0$$
Where $$0.529A^0$$ is is the Bohr's radius $$a_0=0.529$$
Substituting $$Z=2$$, $$n=2$$
$$r=2a_0A^0$$
Question 6
1 / -0

Atomic radius is of the order of $$10^{-8}\ cm$$ and nuclear radius is of the order of $$10^{-13}\ cm$$. The fraction of atom occupied by nucleus is:

A
$$10^{-5}$$

B
$$10^{5}$$

C
$$10^{-15}$$

D
none of these

Solution

A nucleus is the positively charged center of the atom consisting of protons and neutrons. It's also known as the "atomic nucleus". Nearly all the mass of an atom is contained within the nucleus, since protons and neutrons have much more mass than electrons

according to qes.
Volume of nucleus = $$\dfrac{4}{3}{\pi}r^3$$ = $$\dfrac{4}{3}\pi({10^{-3}})^3 cm^3$$
Volume of atom = $$\dfrac{4}{3}\pi({10^{-8}})^3cm^3$$

$$\dfrac{V_N}{V_{atom}}$$ $$=$$ $$\dfrac{10^{-39}}{10^{-24}}$$

$$\dfrac{V_N}{V_{atom}}$$ $$=$$ $$10^{-15}$$
Question 7
1 / -0

Which of the following conclusions could not be derived from Rutherford's $$\alpha$$-particles scattering experiment?

A
Most of the space in the atom is empty.

B

The radius of the nucleus is about $$10^5$$ times less than the radius of the atom.

C
Electrons move in a circular path of fixed energy called orbits.

D
Electrons and the nucleus are held together by the electrostatic force of attraction.

Solution

Based on Rutherford's $$\alpha$$-particles scattering experiment, the nuclear model of the atom was proposed as:
(i) Positive charge and most of the mass of the atom is densely concentrated in an extremely small region called the nucleus. The radius of the nucleus is about $$10^5$$ times less than the radius of the atom.
(ii) The electrons revolve around the nucleus in circular paths.
(iii) Electrons and the nucleus are held together by electrostatic forces of attraction.
The revolution of the electron in a circular orbit is not expected to be stable. Any particle in a circular orbit would undergo acceleration. During acceleration, charged particles would radiate energy. Thus, the revolving electron would lose energy and finally fall into the nucleus. If this were so, the atom should be highly unstable and hence matter would not exist in the form that we know. The concept of stationary state or orbits with fixed energy was given by Bohr's theory and not by Rutherford's theory.
Question 8
1 / -0

What is the ratio of time periods $$(\dfrac{T_1}{T_2})$$ in $$2^{nd}$$ orbit of hydrogen atom to third orbit of $$He^+$$ ion?

A
$$\dfrac{8}{27}$$

B
$$\dfrac{32}{27}$$

C
$$\dfrac{27}{32}$$

D
$$\dfrac{27}{8}$$

Solution

$$\dfrac{T_H}{T_{He}}=\dfrac{n_1^3t_2^2}{n_2^3t_1^2}$$

$$= \dfrac{8\times4}{3^3}=\dfrac{32}{27}$$

The ratio is $$32:27$$.
Question 9
1 / -0

A single electron orbits a stationary nucleus of charge $$+Z$$, where $$Z$$ is a constant. It requires 47.2 eV to excite electron from second Bohr orbit to third Bohr orbit, find the value of $$Z$$.

A
1

B
3

C
5

D
4

Solution

Position is $$n_1=2 \ \Rightarrow n_2=3$$ and $$\Delta E=47.2eV$$
We have $$\Delta E=13.6z^2(\dfrac{1}{n_1^2}− \dfrac{1}{n_2^2})eV$$
$$47.2=13.6z^2(\dfrac{1}{2^2}− \dfrac{1}{3^2})$$
$$z=5$$
Question 10
1 / -0

The nucleus of the atom $$\left( Z>1 \right) $$ consists of:

A
Proton and neutron

B
Proton and electron

C
Neutron and electron

D
Proton, neutron and electrons

Solution

The atomic nucleus is the central area of the atom. It is composed of two kinds of subatomic particles: protons and neutrons.The protons and neutrons held together to form the dense area of the nucleus.

For atoms havng $$Z>1$$ nucleus contains protons and neutrons.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Structure of the Atoms Test - 46

Result

Structure of the Atoms Test - 46

Score

-

Rank

-

SHARING IS CARING

Question 1

$$2.15\times { 10 }^{ -11 }$$

$$0.191\times { 10 }^{ -10 }$$

$$2.389\times { 10 }^{ -12 }$$

$$0.239\times { 10 }^{ -10 }$$

Solution

Question 2

Most of the $$\alpha$$-particles passed through the gold foil undeflected.

A small fraction of the $$\alpha$$-particles was deflected by small angles.

A large number of the $$\alpha$$-particles were bounced back.

A very few $$\alpha$$-particles (~1 in 12,000) were bounced back.

Solution

Question 3

The positive charge is concentrated in a very small volume of the atom.

The positive charge is scattered with the electrons throughout the atom.

The volume occupied by the nucleus is half of the volume of atom.

Most of the space in the atom is occupied by the neutrons.

Solution

Question 4

Overall neutrality of atom

Spectra of hydrogen atom

Position of electrons, protons and neutrons in atom

Stability of atom

Solution

Question 5

$$3a_0$$

$$a_0$$

$$\dfrac{3}{2}a_0$$

$$2a_0$$

Solution

Question 6

$$10^{-5}$$

$$10^{5}$$

$$10^{-15}$$

none of these

Solution

Question 7

Most of the space in the atom is empty.

The radius of the nucleus is about $$10^5$$ times less than the radius of the atom.

Electrons move in a circular path of fixed energy called orbits.

Electrons and the nucleus are held together by the electrostatic force of attraction.

Solution

Question 8

$$\dfrac{8}{27}$$

$$\dfrac{32}{27}$$

$$\dfrac{27}{32}$$

$$\dfrac{27}{8}$$

Solution

Question 9

1

3

5

4

Solution

Question 10

Proton and neutron

Proton and electron

Neutron and electron

Proton, neutron and electrons

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.