**Q1. The mass of one Avogadro number of helium atom is**

(a) 1.00 g

(b) 4.00 g

(c) 8.00 g

(d) 6.02 × 1023 g

**Q2. The maximum electron capacity of any orbital is**

(a) 2

(b) 6

(c) 14

(d) Cannot be determined unless the principal quantum number is known

**Q3. The names of the scientists, Newlands, Mendeleev and Meyer are associated with the development of**

(a) Atomic structure

(b) Metallurgy

(c) Periodic table of elements

(d) Discovery of elements

**Q4. The nuclear particles that are assumed to hold nucleons together are**

(a) Electrons

(b) Positrons

(c) Neutrons

(d) Mesons

**Q5. The nucleus of a hydrogen atom consists of**

(a) One proton

(b) One proton + two neutrons

(c) One neutron only

(d) One electron only

**Q6. A molecule whose electrons are distributed unsymmetrical is said to be **

(a) Ionised

(b) Non-ionised

(c) Polar

(d) Non-polar

**Q7. Bohr’s theory of fixed orbits contradicts**

(a) Coulomb’s law

(b) Planck’s theory

(c) de Broglie relation

(d) Uncertainty principle

**Q8. Evidence for the existence of energy level in atom is supplied by**

(a) Atomic numbers

(b) Atomic radii

(c) Spectral lines

(d) Mass defects

**Q9. For the dumb bell shaped orbital, the value of l is**

(a) 3

(b) 1

(c) 0

(d) 2

**Q10. Which quantum number cannot have an integral value?**

(a) n

(b) l

(c) m

(d) s

**Q11. How many orbitals make up any s-sublevel?**

(a) 1

(b) 3

(c) 5

(d) 7

**Q12. According to Bohr’s theory, an electron in one Bohr stationary orbit can go to a higher stationary orbit**

(a) By emission of electromagnetic radiation

(b) Without any absorption or emission of electromagnetic radiation

(c) With absorption of any electromagnetic radiation

(d) With absorption of electromagnetic radiation of a particular frequency

**Q13. According to Bohr’s theory of hydrogen atom, the angular momentum of the electron in the fourth orbit is given by**

(a) h/2𝜋

(b) 4h/𝜋

(c) h/𝜋

(d) 2h/𝜋

**Q14. According to Einstein’s mass-energy relation**

(a) E = m^2 c

(b) E = mc

(c) E = mc^2

(d) E = vmc

**Q15. According to Heisenberg’s uncertainty principle; it is not possible to determine**

(a) The position of the electron accurately

(b) The momentum of the electron accurately

(c) Simultaneously the position and momentum of an electron accurately

(d) None of these

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