Question

1. which of the following statements is true?

a. the principal quantum number (n) describes the shape of an orbital.
b. the angular momentum quantum number (l) describes the size and
energy associated with an orbital.
c. the magnetic quantum number (ml) describes the orientation of the
orbital.
d. an orbital is the path that an electron follows during its movement in
an atom.
e. all of the above are true.

Explanation:

• Option A: The principal quantum number (\(n\)) describes the size and energy of the orbital, not the shape. The angular momentum quantum number (\(l\)) describes the shape. So A is false.
• Option B: The angular momentum quantum number (\(l\)) describes the shape of the orbital, while the principal quantum number (\(n\)) describes size and energy. So B is false.
• Option C: The magnetic quantum number (\(m_l\)) describes the orientation of the orbital in space. This is correct.
• Option D: An orbital is a region in space where there is a high probability of finding an electron, not a path an electron follows (that was the old Bohr model idea, which is incorrect for electrons in atoms). So D is false.
• Option E: Since A, B, and D are false, E is also false.

Answer:

C. The magnetic quantum number (\(m_l\)) describes the orientation of the orbital.