Tag: neutrons

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Questions Related to neutrons

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

The mass of neutron is of the order of: 

  1. ${10}^{-27} kg$
  2. ${10}^{-26} kg$
  3. ${10}^{-25} kg$
  4. ${10}^{-24} kg$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The mass of neutron is of the order of $\displaystyle {10}^{-27} kg$

It is equal to $\displaystyle 1.674 \times {10}^{-27} kg$ or $\displaystyle 1.674 \times {10}^{-24} g$. It is also equal to 1.0087 amu.

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

The mass of $ _{3}^{7}{Li}$ is $0.042$ less than the mass of $3$ protons and $4$ neutrons. The binding energy per nucleon in $ _{3}^{7}{Li}$ is:

  1. $5.6 MeV$
  2. $56 MeV$
  3. $0.56 MeV$
  4. $560 MeV$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The mass defect for $\displaystyle _3^7Li$  is $\displaystyle \Delta m = 0.042$  amu.
1 amu $\displaystyle =931.5$ MeV
Binding energy $\displaystyle = 0.042 \times 931.5 = 39.123$ MeV
Total number of nucleons in $\displaystyle _3^7Li$  is 7 (3 protons and 4 neutrons).
Binding energy per nucleon $\displaystyle =  \dfrac {39.123}{7} = 5.6$ MeV.

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

The introduction of a neutron into the nuclear composition of an atom would lead to a change in:

  1. its atomic mass

  2. its atomic number

  3. the chemical nature of the atom

  4. number of the electron also
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The introduction of a neutron into the nuclear composition of an atom would lead to a change in its atomic mass.
However, its atomic number, the chemical nature of the atom and the number of the electron s will remain unchanged as they are related to the number of protons and are independent of the number of neutrons.

Note: The atomic mass is equal to the sum of the number of protons and the number of neutrons. Chemical properties depends on number of electrons which are equal to number of protons in neutral atom. They are also equal to atomic number.

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

What is the order of density of neutron?

  1. $10^3$ kg/cc
  2. $10^6$ kg/cc
  3. $10^{12}$ kg/cc
  4. $10^2$ kg/cc
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

$Radius\ of\ neutron = 1\times 10^{-13}$
$\therefore$ volume $=\dfrac{4}{3}\times \pi  r^{3} = \frac{4}{3}\times \pi (1\times 10^{-13})^{3} = \dfrac{4}{3}\times \pi \times 10^{-39}$
Mass of neutron $=1.6\times 10^{-27}$
$\therefore$ Density $=\dfrac{mass}{volume}$ $=\dfrac{3\times 1.6\times 10^{-27}}{4\times \pi \times 10^{-39}} = \dfrac{4.8}{4\times \pi }\times 10^{12}$ kg/cc

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

If A = Atomic mass, Z = Atomic number, then number of neutrons is equal to ?

  1. $A - Z$
  2. $A + Z$
  3. $Z - A$
  4. $\frac{Z}{A}$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

If A = Atomic mass, Z = Atomic number then the number of neutrons is equal to: 


$ A$ = Atomic mass = Number of protons + Number of neutrons

$Z$ = Atomic Number = Number of protons$

$A$ = $Z$ + Number of neutrons

Number of neutrons = $Z-A$

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

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

  1. $e, p, n, \alpha$
  2. $n, p, e, \alpha$
  3. $n, p, \alpha, e$
  4. $n, \alpha, p, e$
Reveal answer Fill a bubble to check yourself
D Correct answer
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.


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

Which of the following doesn't have charge?

  1. Proton

  2. Neutron

  3. Electron

  4. Isotope

  5. Ion
Reveal answer Fill a bubble to check yourself
B Correct answer
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