Tag: structure of the atom

Questions Related to structure of the atom

The order (lowest to highest) of e/m (charge/mass) ratio for electron (e), proton (p), neutron (n) and alpha particle $(\alpha)$ is:

chemistry structure of the atom neutrons discovery of neutrons structure of atoms

  1. $e, p, n, \alpha$

  2. $n, p, e, \alpha$

  3. $n, p, \alpha, e$

  4. $n, \alpha, p, e$

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Correct Option: D
Explanation:
The increasing order (lowest to highest) of e/m (charge/mass) ratio is $ n < \alpha < p < e$.Neutron being neutral has zero charge and lowest e/m ratio. An electron has a unit charge but negligible mass. Hence, the electron has maximum e/m ratio.For an alpha particle, the e/m ratio is 2/4 or 0.5.For proton, e/m ratio is 1/1 or 1.


Which of the following doesn't have charge?

chemistry structure of the atom neutrons discovery of neutrons structure of atoms

  1. Proton

  2. Neutron

  3. Electron

  4. Isotope

  5. Ion

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Correct Option: B
Explanation:

Neutron has zero unit charge.
The neutron is a subatomic particle, symbol n or $n^0$, with no net electric charge and a mass slightly larger than that of a proton. Protons and neutrons, each with mass approximately one atomic mass unit, constitute the nucleus of an atom, and they are collectively referred to as nucleons

Neutron does not get deflected in the presence of electric field.

chemistry structure of the atom neutrons discovery of neutrons structure of atoms

  1. True

  2. False

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Correct Option: A
Explanation:

Neutrons are neutral particles. Thus, they are not affected by the electric field.

Hence, they does not get deflected in the presence of electric field.

 Which of the following would not be attracted or deflected while traveling through an electric field?
I. Gamma ray
II. Beta particle
III. neutron.

chemistry structure of the atom neutrons discovery of neutrons structure of atoms

  1. i only

  2. ii only

  3. i and ii Only

  4. i and iii only

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Correct Option: D
Explanation:

Gamma rays and neutrons have no charge as they are neutral, hence, these would not be attracted or deflected while traveling through an electric field.

Doubly magic nucleus is:

chemistry structure of the atom neutrons discovery of neutrons structure of atoms

  1. $ _{ 82 }^{ 207 }{ Pb }$

  2. $ _{ 82 }^{ 206 }{ Pb }$

  3. $ _{ 82 }^{ 208 }{ Pb }$

  4. $ _{ 83 }^{ 209 }{ Bi }$

Show answer
Correct Option: C
Explanation:

Doubly magic nucleus is $\displaystyle _{ 82 }^{ 208 }{ Pb }$. It has 82 protons and $\displaystyle 208-82=126$ neutrons. 82 and 126 are magic numbers.