Tag: discovery of charged particles

Questions Related to discovery of charged particles

The nucleus of the hydrogen atom is called as:

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

  1. neutron

  2. electron

  3. proton

  4. nucleons

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Correct Option: C
Explanation:

The nucleus of Hydrogen atom is called as proton as it has only $1$ proton in it . Thus correct answer is option C.

Nucleus is composed of two kinds of subatomic particles: 

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

  1. protons and neutrons

  2. electrons and neutrons

  3. protons and electrons

  4. none of the above

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Correct Option: A
Explanation:

Nucleus is composed of protons and neutrons.

An atom has two main regions. Which are those?

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

  1. Planetary electrons and energy levels

  2. Nucleus and kernel

  3. Principal energy levels and energy sublevels

  4. Nucleus and energy levels

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Correct Option: D
Explanation:

An atom has two main regions, these include nucleus and energy levels.
Nucleus contains protons and neutrons. Electrons revolve in circular energy levels.

The nucleus of the atom consists of:

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

  1. protons and neutrons

  2. protons and electrons

  3. neutrons and electrons

  4. protons, neutrons and electrons

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Correct Option: A
Explanation:

The nucleus of the atom consists of protons and neutrons. Electrons are present in extra nuclear part.
Note: Protons, electrons and neutrons are subatomic particles.

Radius of a nucleus is proportional to:

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

  1. $A$

  2. ${A}^{{1}/{3}}$

  3. ${A}^{2}$

  4. ${A}^{{2}/{3}}$

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Correct Option: B
Explanation:

Radius of a nucleus is proportional to $\displaystyle {A}^{{1}/{3}}$
$\displaystyle r=(1.4 \times 10^{-15}) \times {A}^{{1}/{3}}$
Where r is the radius of the nucleus with mass number A.
Here, the unit of radius is meters.  

The ratio of the volume of the atom and the volume of the nucleus is:

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

  1. ${10}^{10}$

  2. ${10}^{12}$

  3. ${10}^{15}$

  4. ${10}^{20}$

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Correct Option: C
Explanation:

The ratio of the volume of the atom and the volume of the nucleus is $\displaystyle 10^{15}$

The radius of an atomic nucleus is of the order of $\displaystyle {10}^{-13} cm$ or $\displaystyle {10}^{-15} m$ or one Fermi unit.

On the other hand, the radius of an atom is of the order of $\displaystyle {10}^{-8} cm$ or $\displaystyle {10}^{-10} m$ or one angstrom unit.

Note:
The radius of nucleus is much smaller than atomic radius.

The ratio of atomic radius to radius of nucleus is $\displaystyle \dfrac {{10}^{-10} m}{{10}^{-15} m}=10^5$

Volume is proportional to cube of radius.

The ratio of atomic radius to radius of nucleus is $\displaystyle  (10^5)^3 = 10^{15}$

Size of the nucleus is:

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

  1. $1A^0$

  2. $10^{-16}m$

  3. $10^{-15}m$

  4. $10^{-14}m$

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Correct Option: C
Explanation:

According to Rutherford the nucleus size is ${ 10 }^{ -15 }m$.

Size of the atom ranges from $0.1$to $0.5nm$ 

Which is characteristic of unstable nucleus?

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

  1. $n/p$ ratio is high

  2. Low binding energy

  3. High packing fraction

  4. None of these

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Correct Option: A,B,C
Explanation:

It is the balance of protons and neutrons in a nucleus which determines whether a nucleus will be stable or unstable. Other factors that influence the stability of nucleus are binding energy and high packing fraction. 

So, the characteristics of unstable nucleus are
  1. $\dfrac{n}{p}$ ratio is high
  2. Low binding energy
  3. High packing fraction

The density of nucleus is of the order of:

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

  1. ${ 10 }^{ 5 }kg{ m }^{ -3 }$

  2. ${ 10 }^{ 10 }kg{ m }^{ -3 }$

  3. ${ 10 }^{ 17 }kg{ m }^{ -3 }$

  4. ${ 10 }^{ 25 }kg{ m }^{ -3 }$

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Correct Option: C
Explanation:

The density of nucleus is about $2.3\times { 10 }^{ 17 }{ ㎏ }/㎥$. The density is same for all nuclei. Thus density of nucleus is of the order ${ 10 }^{ 17 }{ ㎏ }/㎥$

The radius of nucleus is:

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

  1. proportional to its mass number

  2. inversely proportional to its mass number

  3. proportional to the cube root of its mass number

  4. not related to its mass number

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Correct Option: C
Explanation:
The radius of a nucleus (r) is proportional to the cube root of its mass number (A).
The approximate law is $r = r _0 \times A^{ 1/3 }$
where $r _0 = 1.2 \times 10^{ -15 }\ m$
option C is correct