1st Year Chemistry Atomic Structure MCQs

If you are searching for 1st Year Chemistry Atomic Structure MCQs, then this is the place to get them. An atom consists of electrons, protons, and neutrons. These were revealed by different scientists. Electrons are the negative charged particles, Protons are the positively charged and neutrons are the neutrally charged particles. They all have different stories of discovery and have different and specific properties. Measurement of e/m value and charge on an electron is done in different ways. In order to explain an atom, different scientists made different theories. Different spectra were studied. There are some rays called x-rays were produced from electrons. An atomic model was rejected which was made by Bohr. Later the concept of Quantum numbers was made for the atoms which were thought to be successful. Different scientists worked on some rules to make this atomic model perfect. So, have a look at the important MCQs of this chapter to prepare for the Entry test.

1st Year Chemistry Atomic Structure MCQs

KEY POINTS

 

Question#1. Isotopes differ in:

• Properties with respect to their mass number
• Properties with respect to their proton number
• Isotopes don’t differ as they have same number of electrons and protons
• All of the above

Question#2. Isotopes are:

• Chemically similar
• Physically dissimilar
• Chemically dissimilar
• Both a and b

Question#3. Ionization energy depends upon:

• Atomic/ionic radii
• Proton to electron ratio
• Shielding effect
• All of the above

Question#4. 2^nd ionization energy of Mg is higher than the first because:

• Metallic character of Mg⁺¹ is less than that of Mg
• Nuclear pull for Mg⁺¹electron is more than that for the Mg atom
• Size of Mg⁺¹ is greater than Mg⁺²
• Both a and b

Question#5. With the increasing atomic number, ionization energy increases along a period because:

• No change in shielding effect along a period
• Nuclear pull increases with the increase in the number of protons
• Atomic/ionic size decreases along a period
• All of the above

Question#6. The correct set of four quantum numbers for the valence electron of rubidium (Z = 37) is:

• n = 5, 1 = 0, m = 0 and s = +1/2
• n = 5, 1 = 1, m = 1 and s = +1/2
• n = 5, 1 = 1, m = 0 and s = +1/2
• n = 6, 1 = 0, m = 0 and s = +1/2

Question#7. The electron configuration of K(19) is:

• 1s³ 2s³ 2p⁵ 3s³ 3p⁵
• 1s² 2s² 2p⁶ 3s² 2p⁵ 4s²
• 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
• None of the above

Question#8. The number of d-electrons in Fe⁺² (Z=26) is not equal to:

• p electrons in Ne (Z = 10)
• d electrons in Fe (Z = 26)
• s electrons in Mg (Z = 12)
• p electrons in Ar (Z = 17)

Question#9. The electronic configuration of an element is 1s² 2s² 2p³. This represents a/an:

• Ground state
• Hybridized state
• Excited-state
• Molecular state

Question#10. In which of the following, all have the same number of electrons:

• Cl^–, Br^– and I^–
• H^–, H and H⁺
• F^–, Ne and Na⁺
• Li⁺, Na⁺ and K⁺

Question#11. Identify the correct order of increasing energy:

• 1s < 2s < 3s
• 2s > 3s > 1s
• 1s > 2s > 3s
• None of the above

Question#12. The shapes of s orbitals is circular and their size:

• Increase with the increase in principal quantum number
• Decrease with the increase in principal quantum number
• Remains the same with the change in principal quantum number
• None of the above

Question#13. The place between the two orbitals is called:

• Free zone
• Nodal surface
• Neutral zone
• Resonance area

Question#14. Shapes of p orbitals:

• Circular
• Dumb-bell
• Elliptical
• Complex

Question#15. The correct number of degenerate orbitals:

• s = 2, p = 6, d = 10, f = 14
• s = 3, p = 1, d = 5, f = 7
• s = 1, p = 3, d = 5, f = 7
• s = 1, p = 3, d = 7, f = 5

Question#16. The ion that is iso-electronic with CI atom is:

• CN^–
• O⁺₂
• N⁺₂
• O^–₂

Question#17. Which of the following particles would on losing an electron has its outermost p-orbital as half-filled?

• Nitrogen atom
• O⁺ ion
• P^-1 ion
• S⁺¹ ion

Question#18. The ionic specie having more electrons than neutrons is:

• Mg⁺²
• O^2–
• Na⁺
• F^-1

Question#19. Which pair of electrons of elements will have the same chemical properties?

• 2, 24
• 2, 4
• 13, 22
• 3, 11

Question#20. An orbital which is spherically symmetrical is:

• p-orbital
• s-orbital
• d-orbital
• f-orbital

Question#21. The value of e/m for the electron is:

• 1.7588 x 10¹¹ kg C^-1
• 1.7588 x 10^-11 Ckg^-1
• 1.7588 x 10¹¹ kg C^-1
• 1.7588 x 10¹¹ Ckg^-1

Question#22. A nodal plane in an orbital is the plane where the electron density is:

• Maximum
• -ve
• Zero
• +ve

Question#23. How many times the mass of neutrons is greater than the mass of an electron?

• 1480
• 2000
• 1840
• 1200

Question#24. The mass of an oxygen atom is:

• 2.657 x 10^-23g
• 2.657 x 10²³
• 16g
• 32g

Question#25. The mass of a neutron is:

• Same as that of proton
• A little bit smaller than that of proton
• Slightly more than that of proton
• Slightly less than that of proton

Question#26. The smallest charge of electricity which has been measured on any particle is:

• Charge on the positive ray of He gas
• Charge on particles
• Charge on any droplet in Millikan Experiment
• Charge on an electron

Question#27. Which of the following has highest ionization energy value?

• Li
• Be
• H
• He

Question#28. Greater shielding effect corresponds to ionization energy value:

• Greater
• Lesser
  
• Remain the same
• No effect

Question#29. The mass of a proton is:

• 9.1 x 10^-10 g
• 9.1 x 10^-18 g
• 1.672 x 10^-27 kg
• 9.1 x 10^-31 kg

Question#30. Which group shows the abnormal behavior in trend of ionization energy in periods?

• Group I-A
• Group III-A
• Group-VI-A
• Both b and c