Tag: discovery of subatomic particles

Questions Related to discovery of subatomic particles

Absolute mass of electron is equal to __________.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $9.109\times10^{-31}$ kg

  2. $-1.602\times10^{-31}$ kg

  3. $1.672\times10^{-27}$ kg

  4. $1.647\times10^{-27}$ kg

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Correct Option: A
Explanation:

The mass of an electrons is $9.109\times10^{-31}$ kg.


Hence the correct option is A.

Absolute mass of neutrons is ____ .

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $9.109\times10^{-31}$ kg

  2. $-1.602\times10^{-31}$ kg

  3. $1.672\times10^{-27}$ kg

  4. $1.674\times10^{-27}$ kg

Show answer
Correct Option: D
Explanation:

The mass of neutrons is $1.674\times10^{-27}$ kg

An atom does not carry any electric charge because it _____________.

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. has an equal number of charged and non charged particles

  2. has neutrons in their nuclei

  3. has an equal number of electrons and protons, hence positive and negative charge gets neutralized.

  4. has an equal number of neutrons and protons

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Correct Option: C
Explanation:

Equal number of negatively charged electrons and positively charged protons would give a neutral atom which would thus not have any electric charge.

The number of protons in calcium is :

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. $20$

  2. $21$

  3. $22$

  4. $23$

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Correct Option: A
Explanation:

The atomic number is the number of protons in an atom of an element. The atomic number of calcium in the periodic table is 30 and hence calcium has 30 protons in its nucleus.

Which of the following has negligible weight as compared to others?

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. Proton

  2. Neutron

  3. Electron

  4. Isotope

  5. Hydrogen ion

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Correct Option: C
Explanation:

Option $C$ is the correct answer.

Mass of an electron is very negligible. It is $ {9.1}{\times}{10}^{-31} $ Kg.

Which of the following is neutral and weighs 1 amu?

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. Proton

  2. Neutron

  3. Electron

  4. Isotope

  5. Ion

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Correct Option: B
Explanation:

A neutron is electrically neutral particle. And its mass is 1 amu or $ {1.67} $ $ {\times} $ $ {10}^{-27} $ Kg

Thus, option $B$ is the correct answer.

Which of the following has negative charge and is present in atom as pairs with opposite spin?

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. Proton

  2. Neutron

  3. Electron

  4. Isotope

  5. Ion

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Correct Option: C
Explanation:

Option $C$ is the correct answer.

An electron is a negatively charged particle. In an orbital, if two electrons are present together, they should and must have opposite spins. Because, no two electrons can be identically same.

If two atoms are isotopes, in what characteristic do they differ? 

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. Number of protons

  2. Number of neutrons

  3. Number of electrons

  4. Atomic number

  5. Electronic charge

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Correct Option: B
Explanation:

Isotopes are atoms with the same number of protons but that have a different number of neutrons.

The ratio of the neutrons present in nitrogen atom and a silicon atom is: 

(Mass number of nitrogen and silicon is 14 and 28 respectively)

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. 7 : 3

  2. 3 : 7

  3. 1 : 2

  4. 2 : 1

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Correct Option: C
Explanation:

For nitrogen; atomic number = 7 and mass number = 14 

$\therefore$ Number of neutrons $= 14-7 = 7$
For silicon; atomic number = 14 and mass number = 28 
$\therefore$ number of neutrons $= 28-14= 14$
$\therefore$ Ratio of number of neutrons in nitrogen and silicon $= 7:14 = 1:2$

Though the three fundamental particles are present in almost all elements, one element does not have one of them. Identify the particle

chemistry atom fundamental particles of an atom the structure of atoms discovery of subatomic particles

  1. neutron

  2. proton

  3. electron

  4. nucleons

Show answer
Correct Option: A
Explanation:

Neutron is not present in hydrogen. Electronic configuration of hydrogen is 1 $( _1H^1)$.