JEE Main 2020 & NEET 2020: Get important MCQs (with answers) from NCERT book of CBSE Class 11 Chemistry (Chapter 2 - Structure of Atom). These important MCQs are based on topics & concepts from which questions have been frequently asked in previous engineering entrance exams (like JEE Main, WBJEE etc) and medical entrance exams (like NEET). Answers of all the questions are provided with the questions for convenience. Students preparing for NEET 2020 & JEE Main 2020 are recommended to try these questions and check their preparation level for the exams. These questions are also important for the students preparing for the upcoming Chemistry exam.
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JEE Main 2020 & NEET 2020: Important MCQs from NCERT book of CBSE Class 11 Chemistry (Chapter 2 - Structure of Atom):
1. Which of the following options does not represent ground state electronic
configuration of an atom?
(i) 1s2 2s2 2p6 3s2 3p6 3d8 4s2
(ii) 1s2 2s2 2p6 3s2 3p6 3d9 4s2
(iii) 1s2 2s2 2p6 3s2 3p6 3d10 4s1
(iv) 1s2 2s2 2p6 3s2 3p6 3d5 4s1
2. Which of the following statements about the electron is incorrect?
(i) It is a constituent of cathode rays
(ii) The mass of an electron is equal to the mass of a neutron.
(iii) It is a basic constituent of all atoms.
(iv) It is a negatively charged particle.
3. How many angular nodes for 4d orbital?
4. Total number of orbitals associated with the third shell will be __________.
5. Two atoms are said to be isobars if
(i) they have the same atomic number but different mass number.
(ii) they have the same number of electrons but different number of neutrons.
(iii) they have the same number of neutrons but different number of electrons.
(iv) sum of the number of protons and neutrons is same but the number of
protons are different.
6. Which of the following properties of atom could be explained correctly by Thomson Model of atom?
(i) Overall neutrality of atom.
(ii) Spectra of hydrogen atom.
(iii) Position of electrons, protons and neutrons in atom.
(iv) Stability of atom.
7. Orbital angular momentum depends on __________.
(ii) n and l
(iii) n and m
(iv) m and s
8. Chlorine exists in two isotopic forms, Cl-37 and Cl-35 but its atomic mass is 35.5. This indicates the ratio of Cl-37 and Cl-35 is approximately
9. Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons?
(i) Pauli’s exclusion principle.
(ii) Heisenberg’s uncertainty principle.
(iii) Hund’s rule of maximum multiplicity.
(iv) Aufbau principle.
10: Which of the following statement is not correct about the characteristics of cathode rays?
(i) They start from the cathode and move towards the anode.
(ii) They travel in straight line in the absence of an external electrical or
(iii) Characteristics of cathode rays do not depend upon the material of
electrodes in cathode ray tube.
(iv) Characteristics of cathode rays depend upon the nature of gas present
in the cathode ray tube.