*1. Who is regarded as the Father of Modern Chemistry?
(a) Rutherford
(b) Einstein
(c) Lavoisier
(d) C.V. Raman
(e) None of the above/More than one of the above
[65th B.P.S.C. (Pre) 2019]
Ans. (c) Lavoisier
- Antoine Lavoisier, a French nobleman and chemist, is seen as the father of modern chemistry.
- He is especially known for finding out how oxygen affects burning.
- He was the first to name oxygen (1778) and hydrogen (1783), make a long list of elements, and come up with a new way of naming chemicals.
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2. The positively charged part at the centre of an atom is called as :
(a) Proton
(b) Neutron
(c) Electron
(d) Nucleus
(e) None of the above/More than one of the above
[63rd B.P.S.C. (Pre) 2017]
Ans. (d) Nucleus
- At the centre of an atom is a part that has a positive charge, known as the nucleus.
- The nucleus is a tiny, dense area made up of protons and neutrons.
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4. Which of the following statements about molecular structure is correct :
(a) Neutron and electron are found inside the nucleus and protons revolves around the nucleus.
(b) Electrons and protons are inside the nucleus and neutrons revolve around the nucleus.
(c) Proton and neutrons are inside the nucleus and electrons revolve around the nucleus.
(d) Proton, neutron and electron all are inside the nucleus.
[R.A.S./R.T.S. (Pre) 1992]
Ans. (c) Proton and neutrons are inside the nucleus and electrons revolve around the nucleus
5. Which of the following is not a part of an atom?
(a) Electron
(b) Proton
(c) Neutron
(d) Photon
[M.P.P.C.S. (Pre) 2005]
Ans. (d) Photon
- Atoms are made up of protons, electrons, and neutrons.
- Photons are particles of light energy, which is also known as a “packet” of light.
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6. A single type of atom is found in –
(a) Compounds of minerals
(b) Mixture of minerals
(c) Native elements
(d) None of the above
[53rd to 55th B.P.S.C. (Pre) 2011]
Ans. (c) Native elements
- Native elements are made of just one kind of atom, while compounds are made of two or more different kinds of atoms.
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*7. The atomic nucleus was discovered by :
(a) Rutherford
(b) Dalton
(c) Einstein
(d) Thompson
[R.A.S./R.T.S.(Pre) 2003]
Ans. (a) Rutherford
- In 1911, Ernest Rutherford figured out that there is a very dense group of protons and neutrons at the center of every atom.
- This was discovered through the Geiger-Marsden gold foil experiment of 1909.
- Dmitri Ivanenko then proposed the idea that the nucleus has protons and neutrons in 1932.
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8. In an atom, neutron was discovered by :
(a) J.J. Thomson
(b) Chadwick
(c) Rutherford
(d) Newton
[Jharkhand P.C.S. (Pre) 2003, U.P.P.C.S. (Pre) 1996, U.P.P.C.S. (Pre) 1995]
Ans. (b) Chadwick
- Chadwick discovered neutrons in 1932.
- They are particles that don’t have an electrical charge and are made when particles are shot at beryllium or other atoms.
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9. Which of the following is not a sub-atomic particle?
(a) Neutron
(b) Proton
(c) Deuteron
(d) Electron
[U.P.P.C.S. (Pre) 2007]
Ans. (c) Deuteron
- Atoms are made up of really tiny particles called subatomic particles.
- These include protons, neutrons and electrons.
- A deuteron is a type of particle that contains both a proton and a neutron.
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*10. Which one of the following pairs constitutes a particle-antiparticle pair?
(a) Electron – Positron
(b) Proton – Neutron
(c) Photon – Electron
(d) Neutron – Neutrino
[U.P.P.C.S. (Mains) 2005]
Ans. (a) Electron – Positron
- The positron is the opposite of the electron.
- It has the same weight, but it carries a positive electric charge instead of a negative electric charge like the electron.
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[Table]
*11. Match List-I with List-II and select the correct answer using the codes given below the lists :
List-I (Characteristic) List-II (Particle)
A. Zero mass 1. Positron
B. Fractional charge 2. Neutrino
C. Fractional spin 3. Quark
D. Integral spin 4. Phonon
Code :
A B C D
(a) 2 3 1 4
(b) 3 2 4 1
(c) 2 3 4 1
(d) 3 2 1 4
[I.A.S. (Pre) 2001]
Ans. (a) 2 3 1 4
- A positron, the antimatter counterpart of the electron, has a spin of 1/2, just like an electron.
- Quarks make up particles called hadrons, with the most common being protons and neutrons that have a fractional electric charge of +2/3e or -1/3e.
- Neutrinos have no electric charge and a very small mass, possibly even zero.
- Phonon is a type of quasiparticle, an excited state in the quantum mechanical quantization of the modes of vibrations.
- Phonons have 0 spin while, the spin of photons is 1.
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12. Which one is a fundamental particle?
(a) Neutron
(b) Proton
(c) S-meson
(d) Quark
[U.P. R.O./A.R.O. (Mains) 2017]
Ans. (d) Quark
- In particle physics, an fundamental particle is a tiny particle that is not made up of any other particles.
- Examples of fundamental particles include quarks, leptons, antiquarks and antileptons, as well as bosons.
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*13. Higgs Boson is also known as :
(a) Electron
(b) Proton
(c) Neutrons
(d) God Particles
[Jharkhand P.C.S. (Pre) 2021]
Ans. (d) God Particles
- The Higgs Boson is a tiny particle in the science of particle physics which was suggested to exist in 1964.
- It was confirmed to be real in 2013 and is sometimes referred to as the ‘God particle’.
- Peter Higgs and Francois Englert, the physicists who discovered the particle, were given the Nobel Prize for Physics in 2013.
- It has been nicknamed the ‘God Particle’ by Nobel Prize winner Leon Lederman in his 1993 book, ‘The God Particle’.
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*16. The efforts to detect the existence of Higgs boson particles have become frequent news in the recent past. What is/are the importance of discovering this particle?
1. It will help us to understand why elementary particles have mass.
2. It will enable us in the near future to develop the technology to transfer matter from one point to another without traversing the physical space between them.
3. It will enable us to create better fuel for nuclear fission.
Select the correct answer using the codes given below:
(a) only 1
(b) only 2 and 3
(c) only 1 and 3
(d) only 1, 2 and 3
[I.A.S. (Pre) 2013]
Ans. (a) only 1
- Everything that we can see in the universe is made up of matter and molecules.
- It’s important to study this so we can understand why some particles have mass.
- The Higgs Boson is a very important particle that is connected to a field called the Higgs field.
- This field gives mass to other basic particles, such as electrons and quarks.
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17. Which particle is free of charge?
(a) α-particle
(b) Electron
(c) Neutron
(d) Proton
(e) None of the above/More than one of the above
[66th B.P.S.C. (Pre) (Re. Exam) 2020]
Ans. (c) Neutron
- The neutron has no charge, while the alpha particle has a positive charge of +2, the proton has a positive charge of +1, and the electron has a negative charge of -1.
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*19. The alpha particle carries two positive charges. Its mass is very nearly equal to that of –
(a) Two protons
(b) Nucleus of an atom of helium
(c) Sum of masses of two positrons and two neutrons
(d) Two positrons, as each positron carries a single positive charge
[I.A.S. (Pre) 1996]
Ans. (b) Nucleus of an atom of helium
- An alpha particle is a type of particle made up of two protons and two neutrons, which is the same as the nucleus of a helium atom.
- It has a positive charge and interacts strongly with other matter.
- Alpha particles are created during alpha decay and they don’t travel far – they can be stopped by a sheet of paper.
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21. Which of the following elements does not contain neutrons?
(a) Oxygen
(b) Nitrogen
(c) Hydrogen
(e) Copper
(d) None of the above/More than one of the above
[64th B.P.S.C. (Pre) 2018]
Ans. (c) Hydrogen
- Hydrogen is made up of 3 different types of atoms :
- The first type, Protium, has no neutrons.
- The second type, Deuterium, has one neutron.
- The third type, Tritium, has two neutron.
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22. Which of the following carries a negative charge?
(a) X-rays
(b) Alpha particles
(c) Beta particles
(d) Gamma rays
[45th B.P.S.C. (Pre) 2002]
Ans. (c) Beta particles
- Alpha particles are positively charged particles.
- Beta particles are negatively charged electrons which come from the center of an atom and have a very small mass.
- Gamma radiation is made up of photons, which move at the speed of light.
- Gamma radiation can move much faster than alpha and beta particles.
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23. In an atom, the order of filling up of the orbitals is governed by –
(a) Aufbau’s principle
(b) Heisenberg’s uncertainty principle
(c) Hund’s rule
(d) Pauli’s exclusion principle
[I.A.S. (Pre) 2001]
Ans. (a) Aufbau’s principle
- The Aufbau principle is used to figure out how the electrons are arranged in an atom, molecule, or ion.
- The principle suggests that electrons are added to the atom one by one, and each electron finds its most stable place (electron orbital) around the nucleus.
- The electrons fill in the lowest energy levels first, before moving onto higher levels (e.g. 1s before 2s).
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24. Regarding the atom of a chemical element, the magnetic quantum number refers to –
(a) Orientation
(b) Shape
(c) Size
(d) Spin
[I.A.S. (Pre) 2003]
Ans. (a) Orientation
- In atomic physics, the magnetic quantum number (m) is one of four numbers that is used to describe the special state and direction of an electron. It tells us the different energy levels within a subshell.
- The principal quantum number is used to describe the electron shell or energy level.
- The azimuthal quantum number describes the shape of an orbital.
- The spin quantum number is used to tell us the spin of the electron in that orbital.
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25. The number of electrons and neutrons in an element is 18 and 20 respectively. Its mass number is –
(a) 22
(b) 2
(c) 38
(d) 20
(e) None of the above/More than one of the above
[65th B.P.S.C. (Pre) 2019]
Ans. (c) 38
- Given that, number of neutrons = 20 & number of electrons = 18
- Thus, number of protons = number of electrons = 18
- Mass number = number of protons + number of neutrons = 18 + 20 = 38
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26. What is the mass number of an element, the atom of which contains two protons, two neutrons and two electrons?
(a) 2
(b) 4
(c) 6
(d) 8
[43rd B.P.S.C. (Pre) 1999]
Ans. (b) 4
- The mass number of an element is the sum of the total number of protons and neutrons inside its nucleus and is represented by A.
- Therefore, mass number A is the number of protons + a number of neutrons.
- Therefore, mass number = 2 + 2 = 4.
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27. The number of neutrons in the nucleus of plutonium nuclide (94Pu242) is :
(a) 94
(b) 148
(c) 242
(d) 336
(e) None of the above / More than one of the above
[66th B.P.S.C. (Pre) 2020]
Ans. (b) 148
- The amount of neutrons inside the center of plutonium nuclide (94Pu242) is 242-94 = 148.
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28. The atoms, in which the number of protons is the same but the number of neutrons is different, is known as –
(a) Isobars
(b) Isomers
(c) Isotones
(d) Isotopes
[U.P.P.C.S. (Mains) 2009, Chhattisgarh P.C.S. (Pre) 2005, Uttarakhand U.D.A./L.D.A. (Pre) 2003]
Ans. (d) Isotopes
- Isotopes are atoms with the same number of protons but different numbers of neutrons.
- This means they have the same atomic number but different atomic mass.
- Each isotope has its own nucleus.
- The isotopes that are unstable and give off radiation are called radioisotopes.
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31. The neutronic group, in the following, is :
(a) 6 C12, 7 N14, 8 O16
(b) 6 C12, 7 N14, 8 N18
(c) 6 C14, 7 N14, 8 O16
(d) 6 C14, 7 N15, 8 O16
[R.A.S./R.T.S. (Pre) 1999]
Ans. (d) 6 C14, 7 N15, 8 O16
- Two particles, called nuclides, are isotones if they have the same number of neutrons, but a different number of protons.
- Boron-12 and Carbon-13 have 7 neutrons each, so they are isotones.
- The same is true of Carbon-14, Nitrogen-15, and Oxygen-16, which all have 8 neutrons.
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32. Radioactivity is measured by –
(a) Hydrometer
(b) Geiger Counter
(c) Seismometer
(d) Ammeter
[U.P.P.S.C. (GIC) 2010]
Ans. (b) Geiger Counter
- The Geiger Counter is a tool used for finding and measuring radiation.
- It can detect radiation like alpha, beta and gamma rays using the ionization created in a Geiger-Muller tube, which is where the instrument gets its name.
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33. Radioactivity was discovered by :
(a) Rutherford
(b) Becquerel
(c) Bohr
(d) Madam Curie
[U.P.P.C.S. (Mains) 2003]
Ans. (b) Becquerel
- In 1896, the French Scientist Henri Becquerel discovered radioactivity while doing research with phosphorescent materials.
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