Federal 11 Unit 2 (Atomic Structure)

1. For which species Bohr’s theory does not apply

a. H
b. He⁺
c. Li²⁺
d. Be

2. From the discharge tube experiment , it is concluded that

a. mass of proton is in fraction
b. matter contains electrons
c. nucleus contains positive charge
d. positive rays are heavier than protons

3. When an electron of mass m and charge e moves with velocity v about the nuclear charge Ze in the circular orbit of radius r, the P.E of electron is given by

a. Ze²/r
b. -Ze²/r
c. Ze²/r²
d. mv²/r

4. Which of following tells about shells of an atom

a. Principal quantum number
b. Azimuthal quantum number
c. Magnetic quantum number
d. Soin quantum number

5. Electronic configuration of specie M²⁺ is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁶ and its atomic weight is 56 number of neutrons in the nucleus of species M is

a. 20
b. 26
c. 28
d. 30

6. The energy of an electromagnetic radiation is 3*10^-12 ergs. What is wavelength in nanometers

a. 400
b. 228.3
c. 3000
d. 662.5

7. Which of following statement is not correct

a. Rydberg’s constant and wave number has same unit
b. Lyman series of hydrogen spectrum occurs in the ultraviolet region
c. The angular momentum of electron in the ground state of hydrogen atom is equal to h/2 pie
d. The radius of first orbit of hydrogen atom is 2.116*10-8 cm in Bohr’s model

9. Which one of following is not isoelectronic pair

a. Mg²⁺ Be²⁺
b. N^3- O^2-
c. N^3- F^–
d. Na⁺ Al³⁺

10. The third line in Balmer series corresponds to an electronic transfer between which Bohr’s orbit in hydrogen

a. 5….>3
b. 5….>2
c. 4….>3
d. 4….>2