DRA D2D 2025 Crash Course (Atomic Structure) PDF

1. Which of the following articles has no charge? o a) Proton o b) Neutron o c) Electron d) Positron 66 o...

1. Which of the following articles has no charge? o a) Proton o b) Neutron o c) Electron d) Positron 66 o 28 2. The atomic number of an element is determined by the number of: 73 o a) Protons 02 o b) Neutrons 62 o c) Electrons e) ur o d) Nucleons ct 3. Which of the following models was proposed by J.J. Thomson? ru St o a) Plum pudding model ic o b) Nuclear model m to o c) Planetary model (A o d) Quantum mechanical model e rs 4. Rutherford's gold foil experiment led to the discovery of: ou o a) Electrons C o b) Nucleus sh o c) Neutrons ra C o d) Protons 25 5. The mass number of an atom is the sum of: 20 o a) Protons and electrons 2D o b) Protons and neutrons D A o c) Neutrons and electrons R D  o d) Only protons 6. In Bohr's model of the atom, electrons move in: o a) Random paths o b) Elliptical orbits c) Circular orbits 66 o 28 o d) Straight lines 73 7. The quantum mechanical model of the atom was developed by: 02 o a) Niels Bohr 62 o b) Ernest Rutherford e) ur o c) Erwin Schrödinger ct o d) J.J. Thomson ru St 8. The isotope of hydrogen that has one neutron is called: ic o ) Protium m to o b) Deuterium (A o c) Tritium e rs o d) Hydrogen-1 ou 9. Which of the following particles is found in the nucleus of an atom? C o a) Electron sh b) Proton ra o C o c) Positron 25 o d) Neutrino 20 10. The Heisenberg Uncertainty Principle is related to the: 2D o a) Position and momentum of a particle D A R D  o b) Energy and time of a particle o c) Mass and volume of a particle o d) Charge and spin of a particle 11. Which of the following represents the principal quantum number? a) l 66 o 28 o b) m 73 o c) n 02 o d) s 62 12. The shape of an s-orbital is: e) ur o a) Spherical ct o b) Dumbbell ru St o c) Double dumbbell ic o d) Complex m to 13. The Pauli Exclusion Principle states that: (A o a) No two electrons in the same atom can have the same set of quantum e numbers rs ou o b) Electrons occupy orbitals of lowest energy first C o c) Electrons fill degenerate orbitals singly first sh o d) None of the above ra 14. The maximum number of electrons that can be accommodated in an f-orbital is: C 25 o a) 2 20 o b) 6 2D o c) 10 D o d) 14 A R D  15. Which of the following is a transition element? o a) Sodium o b) Chlorine o c) Iron 66 o ) Helium 28 16. The electron configuration of an atom with atomic number 15 is: 73 o a) 1s² 2s² 2p⁶ 3s² 3p³ 02 62 o b) 1s² 2s² 2p⁶ 3s¹ 3p⁴ e) o c) 1s² 2s² 2p⁶ 3s² 3p² 3d¹ ur o d) 1s² 2s² 2p⁶ 3s² 3p⁵ ct ru 17. Which element has the electronic configuration [Ar] 4s¹? o a) Potassium St ic m o b) Calcium to o c) Scandium (A o d) Titanium e rs 18. The Aufbau principle is used to determine: ou o a) The order of filling of atomic orbitals C sh o b) The total number of neutrons in an atom ra o c) The shape of atomic orbitals C o d) The charge on an ion 25 20 19. The de Broglie wavelength is associated with: 2D o a) Particles and waves D o b) Only particles A R D  o c) Only waves o d) None of the above 20. The spin quantum number can have values of: o a) +1 and -1 b) +1/2 and -1/2 66 o 28 o c) 0 and 1 73 o d) +1 and 0 02 21. In the Rutherford model, the majority of the atom's volume is: 62 o a) Empty space e) ur o b) Filled with protons ct o c) Filled with electrons ru St o d) Filled with neutrons ic 22. Which of the following atoms has the smallest atomic radius? m to o a) Hydrogen (A o b) Helium e rs o c) Lithium ou o d) Beryllium C 23. The number of valence electrons in nitrogen is: sh o a) 3 ra C o b) 5 25 o c) 7 20 o d) 8 2D 24. Ionization energy is the energy required to: D A R D  o a) Add an electron to an atom o b) Remove an electron from an atom o c) Combine two atoms o d) Split an atom 25. Which of the following elements has the highest electronegativity? 66 28 o a) Fluorine 73 o b) Oxygen 02 o c) Chlorine 62 o d) Nitrogen e) ur 26. An alpha particle consists of: ct o a) Two protons and two neutrons ru St o b) Two protons and two electrons ic o c) One proton and two neutrons m to o d) Two electrons and two neutrons (A 27. The electron affinity of an atom is: e rs o a) The energy change when an electron is added to the atom ou o b) The energy required to remove an electron from the atom C o c) The energy change when an electron is removed from the atom sh d) The energy change when two atoms combine ra o C 28. The Bohr model of the atom is based on: 25 o a) Classical mechanics 20 o b) Quantum mechanics 2D o c) Special relativity D A o d) General relativity R D  29. The atomic mass of an element is the weighted average of the masses of its: o a) Protons o b) Neutrons o c) Electrons 66 o d) Isotopes 28 30. The number of neutrons in an isotope with a mass number of 35 and atomic number 73 17 is: 02 o a) 17 62 o b) 18 e) ur o c) 19 ct o d) 20 ru St 31. Which of the following is not a fundamental particle in the atom? ic o a) Proton m to o b) Neutron (A o c) Electron e rs o d) Photon ou 32. An isotope is defined as an atom with the same number of protons but a different C number of: sh o a) Neutrons ra b) Electrons C o 25 o c) Nucleons 20 o d) Quarks 2D 33. The probability distribution of an electron in an atom is described by: D o a) The Schrödinger equation A R D  o b) The Heisenberg Uncertainty Principle o c) The Pauli Exclusion Principle o d) The Bohr model 34. Which of the following quantum numbers describes the shape of an orbital? a) Principal quantum number (n) 66 o 28 o b) Azimuthal quantum number (l) 73 o c) Magnetic quantum number (m) 02 o d) Spin quantum number (s) 62 35. The energy levels of electrons in an atom are quantized, meaning they: e) ur o a) Can have any value ct o b) Are continuous ru St o c) Have discrete values ic o d) Are random m to 36. The electron configuration of a neutral atom of chlorine (atomic number 17) is: (A o a) 1s² 2s² 2p⁶ 3s² 3p⁵ e rs o b) 1s² 2s² 2p⁶ 3s² 3p⁶ ou o c) 1s² 2s² 2p⁶ 3s¹ 3p⁶ C o d) 1s² 2s² 2p⁶ 3s² 3p³ sh 37. Which of the following elements has a valence electron configuration of 4s² 3d⁴? ra C o a) Titanium 25 o b) Chromium 20 o c) Manganese 2D o d) Iron D A R D  38. The principle that describes the emission of electrons from a metal surface when light of a certain frequency is shone on it is called: o a) Photoelectric effect o b) Compton effect o c) Quantum tunneling 66 o d) Blackbody radiation 28 73 39. The sum of the number of protons and neutrons in an atom is called the: 02 o a) Atomic number 62 o b) Mass number e) o c) Isotope number ur ct o d) Nucleon number ru 40. The dual nature of matter is described by: o a) de Broglie hypothesis St ic m o b) Heisenberg Uncertainty Principle to (A o c) Schrödinger equation e o d) Bohr model rs ou 41. The atomic radius of elements generally increases as you move: C o a) From left to right across a period sh o b) From top to bottom in a group ra c) From right to left across a period C o 25 o d) From bottom to top in a group 20 42. The element with atomic number 12 has an electron configuration of: 2D o a) 1s² 2s² 2p⁶ 3s² D o b) 1s² 2s² 2p⁶ 3s¹ 3p¹ A R D  o c) 1s² 2s² 2p⁶ 2d² o d) 1s² 2s² 2p⁶ 3p² 43. Which of the following particles is not a fermion? o a) Proton b) Neutron 66 o 28 o c) Electron 73 o d) Photon 02 44. The nucleus of an atom is held together by: 62 o a) Electromagnetic force e) ur o b) Gravitational force ct o c) Strong nuclear force ru St o d) Weak nuclear force ic 45. The maximum number of electrons that can be accommodated in the second energy m level (n=2) is: to (A o a) 2 e o b) 6 rs ou o c) 8 C o d) 10 sh 46. The quantum number that indicates the orientation of an orbital around the nucleus ra is: C o a) Principal quantum number (n) 25 20 o b) Azimuthal quantum number (l) 2D o c) Magnetic quantum number (m) D o d) Spin quantum number (s) A R D  47. The term "isoelectronic" refers to species having: o a) The same number of protons o b) The same number of neutrons o c) The same number of electrons o d) The same number of nucleons 66 28 48. Which element has the electronic configuration [Kr] 5s¹ 4d⁵? 73 o a) Yttrium 02 o b) Zirconium 62 o c) Niobium e) ur o d) Molybdenum ct 49. The ionization energy of elements generally decreases as you move: ru St o a) From left to right across a period ic o b) From top to bottom in a group m to o c) From right to left across a period (A o d) From bottom to top in a group e rs 50. The hybridization of carbon in methane (CH₄) is: ou o a) sp C o b) sp² sh o c) sp³ ra C o d) dsp² 25 20 2D D A R D