Tag: neutrons

Questions Related to neutrons

The heaviest subatomic particle is :

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

  1. neutron

  2. positron

  3. electron

  4. proton

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Correct Option: A
Explanation:

Neutron is heaviest subatomic particle among the given subatomic particles with mass of 1.008 amu while proton have mass of 1 amu.

The lightest particle is/are :

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

  1. electron

  2. proton

  3. neutron

  4. $\beta$-particle

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Correct Option: A,D
Explanation:
The electron is the lightest particle of the atom. It has a mass of $ 9.1 \times 10^{-28}$ grams. Comparing this mass to that of the proton's at $1.6726 \times 10^{-24}$ grams, an electron is nearly $0.0005$ times the proton's mass.

Beta particles are high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei. Hence, their mass will similar to that of the electron.

Hence, options A and D are correct.
State whether true or false :

A neutron can be found in all atoms.
chemistry structure of the atom neutrons discovery of neutrons structure of atoms

  1. True

  2. False

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Correct Option: B
Explanation:

The statement, 'Neutron can be found in all atoms' is false.


Neutron is absent in hydrogen atoms. 

The nucleus of $ _1^1H$ contains only a proton. 

So it is not necessary that all atoms have neutron in them.

Assertion : Protons are better projectiles than neutrons.
Reason : The neurons being neutral do not experience repulsion from positively charged nucleus.

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

  1. If both (A) and (R) are correct, and (R) is the correct explanation of (A).

  2. If both (A) and (R) are correct, but (R) is not the correct explanation of (A).

  3. If (A) is correct, but (R) is correct.

  4. If (A) is incorrect, but (R) is correct.

  5. If both (A) and (R) are incorrect.

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Correct Option: D
Explanation:

Neutrons are better projectiles than protons.
The decreasing order of the projectile power is $\displaystyle _0n^1 > _{1}H^{1} > _{1}H^{2}> _{2}He^{4}$
The neurons being neutral do not experience repulsion from positively charged nucleus.
Thus, (A) is incorrect, but (R) is correct.

Arrange the following particle in increasing order of values of e/m ratio : electron (e), proton (p), neutron (n) and $\displaystyle \alpha $-particle $\displaystyle (\alpha) $.

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

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

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

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

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

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Correct Option: B
Explanation:

$\displaystyle n< \alpha < p< e$            

e/m of n = 0
$\displaystyle e/m: : of: : \alpha =\frac{9.58\times 10^{4}}{2}c/g$
e/m of p = $\displaystyle 9.58\times 10^{4}: : c/g$
e/m of e = $\displaystyle 1.7588\times 10^{8}: : c/g$

Which of the following has the greatest mass?

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

  1. Electron

  2. Proton

  3. Neutron

  4. Hydrogen cation

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Correct Option: C
Explanation:

Neutron has greatest mass. Proton is a subatomic particle with symbol p and positive electric charge of +1 elementary charge and mass slightly less than that of neutron. Mass of neutron is $1.6749\times10^{-27}  kg$.

Isotone of an element has :

chemistry what is inside atom neutrons discovery of neutrons structure of atoms

  1. Same number of electron

  2. Same number of protons

  3. Same number of neutrons

  4. Same number of neutrons & protons

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Correct Option: C
Explanation:

Isotone of an element has same no. of neutrons

The triad of nuclei that is isotonic is :

chemistry what is inside atom neutrons discovery of neutrons structure of atoms

  1. $^{14} _6C,\,^{15} _7N,\, ^{17} _9F$

  2. $^{12} _6C,\,^{14} _7N,\, ^{19} _9F$

  3. $^{14} _6C,\,^{14} _7N,\, ^{17} _9F$

  4. $^{14} _6C,\,^{14} _7N,\, ^{19} _9F$

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Correct Option: A
Explanation:

The triad of nuclei that is isotonic is  $^{14} _6C,\,^{15} _7N,\, ^{17} _9F$.
Number of neutrons are
$C -14-6=8$
$N-15-7=8$
$F-17-9=8$

The atoms of different elements having the same number of neutrons are known as :

chemistry what is inside atom neutrons discovery of neutrons structure of atoms

  1. isobars

  2. isomers

  3. isotones

  4. isotopes

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Correct Option: C
Explanation:

Two nuclides are isotones if they have same neutron number but different proton number e.g. $boron-12$ and $carbon-13$ both contain 7 neutrons so they are $isotones$.

The nuclides $^{40} _{18}Ar$ and $^{41} _{19}K$ are :

chemistry what is inside atom neutrons discovery of neutrons structure of atoms

  1. isotopes

  2. isobars

  3. isotones

  4. none of these

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Correct Option: C
Explanation:

The two or more species of atoms or nuclei that have the same number of neutrons are called as isotones.


The nuclides $^{40} _{18}Ar$ and $^{41} _{19}K$ are isotones. Because they have the same number of neutron.

So, the correct option is $C$