Tag: the structure of the atom

Questions Related to the structure of the atom

The volume $(V)$ of nucleus of an atom is expressed in terms of mass no. $(A)$ of atom as :

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. $V\propto A$

  2. $V\propto A^{1/3}$

  3. $V\propto A^2$

  4. $V\propto A^3$

Show answer
Correct Option: A
Explanation:

As we know,

$r=r _0\times A^{1/3}$   

where. A is atomic mass no. and
$\displaystyle V _n=\frac{4}{3}\pi r^3$

So, $\displaystyle V _n=\frac{4}{3}\pi[1.33\times 10^{-13}\times A^{1/3}]^3$

$\therefore V _n\propto A\propto mass :no$.

Compared to size of its nucleus, the size of an atom is about :

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. ten times greater

  2. the same

  3. a hundred times greater

  4. one hundred thousand times greater

  5. a thousand times greater

Show answer
Correct Option: D
Explanation:

the radius of nucleus is of the order of $ {10}^{-15} $ whereas the radius of atom is of the order of  $ {10}^{-10} $.

Mirror nuclei are those which have:

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. the same number of protons

  2. the same number of neutrons

  3. the number of protons equal to number of neutrons

  4. the number of neutrons in one equal to the number of protons in the other.

Show answer
Correct Option: D
Explanation:

 Mirror nuclei are nuclei where the number of protons of element one (Z1) equals the number of neutrons of element two (N2).

$\pi $ - mesons are regarded as the nuclear glue to hold up neutrons and protons in nucleus.
chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. True

  2. False

Show answer
Correct Option: A
Explanation:

Protons have positive charge. In any nucleus containing two or more protons there will be electrostatic repulsion between the like charges.

In stable nucleus, attractive forces > repulsive forces and in unstable nucleus, attractive forces < repulsive forces.

Meson theory of stability of the nucleus was postulated by the Japanese scientist Yukawa in 1935.
He postulated the existence of a nuclear particle π-meson or pion which acts as a glue binding the protons and neutrons together in the nucleus.

These mesons hold the protons and neutrons together by continuously exchanging position between neutrons and protons in the nucleus. Hence, π-mesons are regarded as the nuclear glue to hold up neutrons and protons in nucleus.

All atoms contain neutrons in their nuclei except:

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. Protium

  2. Helium

  3. Neon

  4. Chlorine

Show answer
Correct Option: A
Explanation:

All atoms except Protium, an isotope of Hydrogen contain neutrons in their nuclei. As Protium has zero neutrons in the nucleus and has mass no 1.


Hence, the correct option is $A$

Outside a nucleus :

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. neutron is stable

  2. proton and neutron both are stable

  3. neutron is unstable

  4. neither neutron nor proton is stable

Show answer
Correct Option: C

The density of nucleus is about _______ times the density of atom.

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. $10^{-14}$

  2. $10^{12}$

  3. $10^{-8}$

  4. $10^{10}$

Show answer
Correct Option: D
Explanation:

The density of nucleus is about $10^{10}$ times the density of atom.
This because the maximum mass of atom is concentrated in nucleus.

The particles present in the nucleus of an atom are :

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. the proton and the electron

  2. the electron and the neutron

  3. the proton and the neutron

  4. none of these

Show answer
Correct Option: C
Explanation:

The particles present in the nucleus of an atom are the proton and the neutron.
Electrons are present outside the nucleus.

The space between a proton and electron in hydrogen atom is :

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. full of air

  2. full of ether

  3. full of electromagnetic radiations

  4. empty

Show answer
Correct Option: D
Explanation:

Hydrogen atom contains one proton in the nucleus and one electron outside the nucleus.
The space between a proton and electron in hydrogen atom is empty.

Nuclides having the same atomic and mass numbers are known as :

chemistry the structure of the atom discovery of charged particles the plum pudding atom discovery of electrons and protons

  1. isotones

  2. isomers

  3. isobars

  4. isotopes

Show answer
Correct Option: B
Explanation:

Nuclides having the same atomic and mass numbers are known as Isomers.

An atom that has an unbalanced ratio of neutrons to protons in the nucleus seeks to become more stable. The unbalanced or unstable atom tries to become more stable by changing the number of neutrons and/or protons in the nucleus. This can happen in several ways:

  • converting neutrons to protons
  • converting protons to neutrons
  • ejecting an alpha particle (two neutrons and two protons) from the nucleus.

 Isotones :any of two or more species of atoms or nuclei that have the same number of neutrons.

Isobars are atoms of different chemical elements that have the same number of nucleons.

Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number.