CBSE Class 11 Chemistry Quantum Model of Atom MCQ Exam

Principle Quantum Number (n)

• Specifies the energy level of the electron
• Determines the size of the orbital
• Can have values of 1, 2, 3, ... (any positive integer)
• Not a valid principle quantum number: 0, 5.5
• Higher the value of n, indicates a higher energy level and farther distance from the nucleus

Angular Momentum Quantum Number (l)

• Defines the subshell of the electron
• Possible values depend on the value of n
• Range: 0 to n-1
• For a given n, possible values of l: 0, 1, 2, ..., n-1
• For a d subshell, l can be 0, 1, 2, or 3

Magnetic Quantum Number (m_l)

• Specifies the orientation of the orbital in space
• Possible values: -l to +l
• For a p subshell (l = 1), possible values of m_l: -1, 0, +1
• Total number of possible values of m_l is 2l + 1

Shape of Orbital and Orbital Angular Momentum

• s-orbitals are spherical in shape
• Orbital angular momentum of an electron is directly proportional to the angular momentum quantum number (l)

Number of Orbitals and Electrons

• Total number of orbitals in a shell with principal quantum number n: n^2
• Number of orbitals in a p subshell: 3
• Maximum number of electrons that can be accommodated in a shell with n = 3: 18

Spin Quantum Number (m_s)

• Can have values of +1/2 or -1/2
• Electrons with opposite spins have the same energy

Electronic Configuration

• Electronic configuration of Neon (Ne): 1s^2 2s^2 2p^6
• In a filled subshell, all orbitals are fully occupied with electrons