Free Shapes of Orbitals MCQs with Answers

1. The shape of a p orbital is

• A. spherical
• B. dumbbell shaped
• C. doughnut shaped
• D. tetrahedral

Explanation: A p orbital has two lobes on opposite sides of the nucleus with a node at the nucleus itself, giving the familiar dumbbell shape, and the three p orbitals lie along the x, y and z axes. Spherical shape belongs to the s orbital. Tetrahedral describes a molecular geometry rather than the shape of a single orbital.

2. The number of orbitals in a d subshell is

• A. 3
• B. 5
• C. 7
• D. 1

Explanation: The number of orbitals in a subshell is 2l plus 1, and for a d subshell l equals 2, giving five orbitals that together hold up to ten electrons. A p subshell has three orbitals and an f subshell seven. Each orbital holds a maximum of two electrons with opposite spins.

3. A node in an orbital is a region where

• A. the electron density is maximum
• B. the probability of finding the electron is zero
• C. the nucleus is located
• D. two orbitals overlap

Explanation: The wave function passes through zero at a node, so the electron is never found there, and the number of nodes increases with the principal quantum number. A 2s orbital has one radial node while a 1s has none. Nodes are a direct consequence of treating the electron as a wave.

4. Shape of orbital is determined by quantum number:

• A. n
• B. l
• C. m
• D. s

Explanation: The azimuthal quantum number l fixes the subshell and therefore the shape, with l equal to 0 giving a spherical s orbital and l equal to 1 giving a dumb-bell shaped p orbital. The principal quantum number n sets the main energy level and size, m sets the orientation in space and s the direction of electron spin. Knowing which quantum number controls which property answers a whole family of questions.