intro
MCQs 1
What leads to the production of positive rays?
Topic: Generation of Positive Rays
Correct Answer: C) By ionizing the gas
- Positive rays, also known as canal rays, are generated in a gas discharge tube.
- The process starts when cathode rays (electron streams) collide with gas molecules in the tube.
- This collision ionizes the gas, meaning it ejects electrons from the gas molecules.
- This results in the production of positive ions or positive rays.
- Therefore, the correct answer is C, "By ionizing the gas".
MCQs 2
What are the potential m values for l ≥ 1 in quantum mechanics?
Topic: Quantum Numbers and Their Significance
Correct Answer: C) -1, 0, +1
- In quantum mechanics, the magnetic quantum number (m) represents the possible orientations of the orbital in space.
- For a given azimuthal quantum number (l), the magnetic quantum number (m) can take values from -l to +l including 0.
- Therefore, for l ≥ 1, the possible m values can be -1, 0, and +1.
- Hence, the correct answer is C, "-1, 0, +1".
Question 3:
Which electron configuration corresponds to the highest energy level?
Topic: Energy Levels and Electron Configuration
Correct Answer: A) N 3, l 2, m 0, s +1/2
- In electron configuration, the principal quantum number (N) represents the energy level of an electron.
- The larger the value of N, the higher the potential energy of the electron.
- However, if the N value is the same, then the energy depends on the azimuthal quantum number (l).
- Therefore, among the given options, the electron with configuration N 3, l 2, m 0, s +1/2 has the highest energy.
- Hence, the correct answer is A, "N 3, l 2, m 0, s +1/2".
Question 4:
Which gas has the maximum e/m ratio in positive rays?
Topic: Positive Rays and Gas Properties
Correct Answer: A) Hydrogen
- The e/m value, or the charge-to-mass ratio, for positive rays is dependent on the mass of the gas used in the gas discharge tube.
- The lighter the mass of the gas, the higher the e/m value.
- Among the given options, hydrogen has the least mass.
- Therefore, the e/m value for positive rays is maximum for hydrogen.
- Hence, the correct answer is A, "Hydrogen".
Question 5:
What is the correct electron configuration of Manganese?
Topic: Electron Configuration of Elements
Correct Answer: A) 3d5, 4s2
- The electron configuration describes how electrons are distributed in the atomic orbitals of an atom.
- Manganese, which is the 25th element on the periodic table, has an electron configuration of 3d5, 4s2.
- Therefore, the correct answer is A, "3d5, 4s2".
Question 6:
How many electrons can an f-sub shell orbital accommodate at maximum?
Topic: Electron Capacity of Atomic Orbitals
Correct Answer: A) 2
- Every orbital in any sub-shell can accommodate a maximum of 2 electrons only.
- This includes the f-sub shell orbital.
- Thus, the correct answer is A, "2".
Question 7:
Which quantum number gives information about the orientation of orbitals?
Topic: Quantum Numbers and Orbital Orientation
Correct Answer: D) Magnetic quantum number
- The quantum numbers define the state of an electron within an atom.
- The magnetic quantum number is the one that tells us about the orientation of an orbital within a subshell.
- It can have values from -l to +l (including 0), where l is the azimuthal quantum number.
- Thus, the correct answer is D, "Magnetic quantum number".
MCQs 8:
What is the total number of unpaired electrons in an atom with the electron configuration 1s2, 2s2, 2p4?
Topic: Electron Configuration and Unpaired Electrons
Correct Answer: B) 2
- The electron configuration 1s2, 2s2, 2p4 indicates there are 2 unpaired electrons in the 2p orbital.
- This is because the 2p orbital can accommodate up to 6 electrons, and it currently has only 4.
- Thus, the correct answer is B, "2".
MCQs 9:
As the value of the principal quantum number ‘n’ increases, what happens to the size of the ‘s’ orbital?
Topic: Orbital Size with Quantum Number
Correct Answer: A) Increase
- The principal quantum number 'n' is directly proportional to the size of the 's' orbital.
- Therefore, as the value of 'n' increases, the size of the 's' orbital also increases.
- Hence, the correct answer is A, "Increase".
MCQs 10:
Where is there a 95% probability of locating an electron in the space around the nucleus?
Topic: Electron Probability and Atomic Orbitals
Correct Answer: C) Atomic orbital
- The atomic orbital is described as the volume of space in which there is a 95% chance of finding an electron.
- An electron's highest probability of being found is at a distance of 0.053nm.
- Therefore, the correct answer is C, "Atomic orbital".
MCQs 11:
What do we call the orbitals that possess identical energy?
Topic: Energy Equivalence in Orbitals
Correct Answer: C) Degenerate orbitals
- The term used for orbitals of the same energy level is "degenerate orbitals".
- This term is applied irrespective of the type of orbital.
- Therefore, the correct answer is C, "Degenerate orbitals".
MCQs 12:
What determines the characteristics of anode rays?
Topic: Impact on Positive Ray Properties
Correct Answer: B) The nature of gas in the discharge tube
- The e/m ratio of the particle in anode rays is dependent on the nature of the gas in the discharge tube.
- As the mass (nature) of the gas changes, the e/m value also fluctuates.
- Thus, the correct answer is B, "The nature of gas in the discharge tube".
MCQs 13:
Which quantum number provides information about the energy level of an electron within an atom?
Topic: Quantum Numbers and Electron Energy
Correct Answer: A) Principal
- The principal quantum number (n) is responsible for providing information about the energy level of an electron in an atom.
- It is also incorporated in the energy formula derived by Bohr.
- Hence, the correct answer is A, "Principal".
Question 14:
How would you accurately illustrate the cross and dot structure of Chlorine atoms?
Topic: Cross and Dot Diagrams
Correct Answer: B) Option B
- The cross and dot diagram represents an atom's electron arrangement.
- In the case of Chlorine, option B gives the correct representation.
- Therefore, the correct answer is B, "Option B".
Question 15:
Compared to the first orbit, how much further is the third orbit of a hydrogen atom from the nucleus?
Topic: Orbital Distances in Hydrogen Atom
Correct Answer: C) Nine times
- The distance of an orbit from the nucleus can be calculated using the formula 0.529n2Ao.
- For the first orbit, it will be 0.529(1)^2Ao = 0.529 Ao, and for the third orbit, it will be 0.529(3)^2Ao = 0.529 × 9 Ao.
- Hence, the correct answer is C, "Nine times".
Question 16:
In which type of orbitals would you find five degenerate orbitals?
Topic: Degenerate Orbitals and Types
Correct Answer: C) d-orbital
- Degenerate orbitals refer to orbitals that have the same energy level.
- Five degenerate orbitals are particularly found in d-orbitals.
- Thus, the correct answer is C, "d-orbital".
MCQs 17:
How many unpaired electrons are there in a ground state Nickel atom? (Atomic number of Ni is 28)
Topic: Unpaired Electrons in Nickel Atom
Correct Answer: A) 2
- The atomic number of Nickel (Ni) is 28, and its electronic configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 3d⁸ 4s².
- By evaluating the outer configuration, we can notice that there are two unpaired electrons.
- Consequently, the correct answer is A, "2".
MCQs 18:
What is the angular momentum of the second orbit?
Topic: Angular Momentum in Orbits
Correct Answer: A) h/π
- The formula for angular momentum is given by nh/2π where 'n' is the orbit number.
- Substituting 'n' with 2 in the formula, we get h/π.
- Therefore, the correct answer is A, "h/π".
MCQs 19:
Which orbital diagram illustrates a violation of the Aufbau principle?
Topic: Violations of the Aufbau Principle
Correct Answer: B) Option B
- The Aufbau principle states that electrons fill up orbitals in order of increasing energy, starting with s-subshell as it has the lower energy level.
- Option B shows a violation of this principle, with the p-subshell being filled before the s-subshell.
- Hence, the correct answer is B, "Option B".
MCQs 20:
Which one of the electrons listed below possesses the most substantial energy?
Topic: Electron Energy Levels
Correct Answer: A) N 3, l 2, m 0, s +1/2
- The energy of an electron is determined by the principal quantum number 'n', as well as the azimuthal quantum number 'l'.
- With the highest combined values of 'n' and 'l', option A holds the electron with the most energy.
- Thus, the correct answer is A, "N 3, l 2, m 0, s +1/2".
MCQs 21:
What is the ratio between the radii of the second and third Bohr orbits for a hydrogen atom?
Topic: Radii of Bohr Orbits in Hydrogen Atom
Correct Answer: C) 4:9
- The radius of an orbit can be calculated using the formula 0.529n^2Ao, where 'n' is the orbit number.
- Substituting 'n' with 2 for the second orbit, and 3 for the third orbit, we get 0.529(2)^2Ao and 0.529(3)^2Ao.
- Consequently, the correct answer is C, "4:9".
Question 22:
For which of the following species is Bohr's theory not applicable?
Topic: Limitations of Bohr's Theory
Correct Answer: C) He2+
- Bohr's theory applies to species containing one electron and not for species having no electron at all.
- Helium 2+ is an example of such a species, as it does not contain any electron.
- Hence, the correct answer is C, "He2+".
- The other species listed do contain electrons, and thus Bohr's theory is applicable to them.
Question 23:
The charge of one gram of electron is:
Topic: Charge Carried by Electrons
Correct Answer: C) 1.7588 × 108
- Since an electron’s mass is 9.109×10-28 g, this means there are about 1/(9.11×10-28) 1.098×1027 electrons present in a gram.
- Given that the charge of one electron is 1.602×10-19 C, we can compute the charge in a gram of electrons: (1.098×1027) (1.602×10-19) C 1.759×108 C.
- Therefore, the correct answer is C, "1.7588 × 108".
Question 24:
Choose the isoelectronic pair.
Topic: Isoelectronic Species
Correct Answer: C) Ar & Ca2+
- Isoelectronic species are those which have an equal number of electrons.
- Argon (Ar) and Calcium 2+ (Ca2+) both have 18 electrons, making them isoelectronic.
- Hence, the correct answer is C, "Ar & Ca2+".
Question 25:
When the 5d orbital is complete, the entering electron goes into
Topic: Electron Orbital Filling Order
Correct Answer: D) 6p
- The electron filling order for orbitals is 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, etc.
- After the 5d orbital has been filled up, the next orbital to be filled is the 6p orbital.
- Therefore, the correct answer is D, "6p".
Question 26:
Maximum number of electrons in M–shell is?
Topic: Atomic Structure - Electrons and Shells
Correct Answer: C) 18
- The maximum number of electrons in a shell is given by the formula 2n2.
- Where n is the principal quantum number.
- For the M-shell, n is 3.
- Therefore, the maximum number of electrons in the M-shell is 2*32 = 18.
Question 27:
The velocity of photon is:
Topic: Waves - Nature of Light
Correct Answer: A) Independent of its wavelength
- The velocity of light is constant, regardless of its wavelength or source.
- This is why all light travels at the same speed, approximately 300,000 kilometers per second in a vacuum.
Question 28:
Which sub-shell is represented by the quantum numbers n4 and l3?
Topic: Quantum Numbers and Sub-Shell Identification
Correct Answer: D) 4f
- The quantum number `l` is used to denote sub-shells: `s` (when `l=0`), `p` (when `l=1`), `d` (when `l=2`), and `f` (when `l=3`).
- Given `n=4` and `l=3`, we find that the sub-shell is `4f`.
Question 29:
The correct electronic configuration notation for Neon (Ne) is?
Topic: Electronic Configuration
Correct Answer: D) 1s2, 2s2, 2p6
- The electronic configuration notation for an atom tells us the distribution of its electrons in different orbitals.
- According to the Aufbau principle, electrons fill up orbitals in order of increasing energy.
- The order of filling of orbitals is as follows: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, and so on.
- Neon has an atomic number of 10, which means that it has 10 electrons.
- The first two electrons in neon fill up the 1s orbital. The next two electrons fill up the 2s orbital. The remaining six electrons fill up the 2p orbital.
- Therefore, the correct electronic configuration notation for neon is 1s2, 2s2, 2p6.
MCQs 30:
What are the quantum number values for 2p orbitals?
Topic: Quantum Numbers for 2p Orbitals
Correct Answer: A) n 2, l 1
- The principal quantum number in a 2p orbital is 2, thus n = 2.
- For a p orbital, the azimuthal quantum number (l) is 1.
- Therefore, for a 2p orbital, the quantum numbers are n = 2, l = 1.
MCQs 31:
Where is the probability of detecting an electron zero between two orbitals?
Topic: Zero Probability Regions for Electrons
Correct Answer: C) Nodal surface
- In quantum mechanics, certain regions show zero probability of finding an electron.
- These regions, termed nodal surfaces, lie between orbitals.
MCQs 32:
Which orbital possesses zero radial nodes?
Topic: Radial Nodes in Orbitals
Correct Answer: D) 4f
- The number of radial nodes in an orbital can be calculated using the formula: Radial nodes = n – l – 1.
- For a 4f orbital, using the formula gives: 4 – 3 – 1 = 0.
- This means a 4f orbital has no radial nodes.
MCQs 34:
Which quantum number determines the shape of an orbital?
Topic: Shapes of Orbitals and Quantum Numbers
Correct Answer: B) l
- The shape of an orbital is defined by the azimuthal quantum number, denoted as 'l'.
- It characterizes the orbital angular momentum.
MCQs 35:
What is the correct term for the quantum number symbolized by "n"?
Topic: Quantum Number Naming Convention
Correct Answer: A) Principal quantum
- In quantum physics, each quantum number has a designated symbol and name for identification.
- The quantum number symbolized by 'n' is known as the Principal quantum number.
- Therefore, the correct answer is A, "Principal quantum".
MCQs 36:
Which quantum number is known as the 'Principal quantum number'?
Topic: Principal Quantum Number
Correct Answer: A) The quantum number symbolized by 'n'
- The Principal quantum number, symbolized by 'n', is one of the four quantum numbers in quantum mechanics.
- It determines the energy of an electron in an atom and the size of the orbital it occupies.
- Therefore, the correct answer is A, "The quantum number symbolized by 'n'".
MCQs 37:
What is the name of the quantum number represented by the symbol 'n'?
Topic: Understanding Quantum Numbers
Correct Answer: D) Principal quantum number
- In quantum mechanics, quantum numbers are used to describe the unique state of a particle, such as an electron in an atom.
- The quantum number symbolized by 'n' is known as the Principal quantum number which determines the energy level and size of the orbital.
- Hence, the correct answer is D, "Principal quantum number".