Thomson's, Rutherford's and Bohr's Atomic Models MCQs

Q1. A science teacher draws a uniform sphere of positive charge and sprinkles tiny negative particles all through it like seeds in a watermelon. Which atomic model is she illustrating on the board?

• A.Bohr's model
• B.Rutherford's model
• C.Dalton's model
• D.Thomson's model

Answer: D. Thomson's model

Thomson pictured the atom as a sphere of uniformly spread positive charge with electrons embedded inside it, like seeds in a watermelon (the plum-pudding picture). The watermelon analogy is the signature of Thomson's model.

Q2. Two students argue about an atomic model in which the positive charge is not concentrated at one point but smeared evenly through the entire volume of the atom. Which model are they discussing?

• A.Bohr's model
• B.Quantum mechanical model
• C.Rutherford's model
• D.Thomson's model

Answer: D. Thomson's model

Smearing the positive charge evenly through the whole atomic volume is unique to Thomson's plum-pudding model. Both Rutherford and Bohr concentrate positive charge in the nucleus.

Q3. A pudding is baked with raisins distributed throughout it; a chef uses this to explain an atom where the negative particles sit inside a positive bulk. If the pudding represents the atom, what do the raisins represent and whose model is this?

• A.Nuclei in Dalton's model
• B.Neutrons in Bohr's model
• C.Electrons in Thomson's model
• D.Protons in Rutherford's model

Answer: C. Electrons in Thomson's model

In the plum-pudding analogy the pudding is the positively charged bulk and the raisins are the embedded electrons. This embedded-electron picture is Thomson's model.