Which diagram most closely
represents Rutherford’s nuclear or planetary model of the atom?
Rutherford’s planetary or nuclear
model is based of observations from the gold foil experiment. In the planetary model, there is a
positively charged nucleus in the center of the atom. And the electrons orbit the
nucleus. So let’s see which of the diagrams
that we have most closely represents this description of the atom. In diagram (A), we have electrons
in orbits around the nucleus. This certainly matches what we’re
looking for. So let’s keep this diagram in
mind. In answer choice (B), we have
positively charged particles in a negative charge. This diagram certainly doesn’t
match what we’re looking for. In fact, it doesn’t match any model
of the atom.
In answer choice (C), we have
particles arranged on the corners of a cube. This diagram is referencing Lewis’s
cubic model of the atom. In answer choice (D), we have
electrons orbiting a central nucleus, which is what we’re looking for. So let’s keep this answer choice in
mind as well. Our final answer choice has
negatively charged particles embedded in positive charge. This certainly doesn’t describe
what we’re looking for, but it does describe the plum pudding model of the atom.
So we’ve eliminated the possible
diagrams to represent the planetary or nuclear model of the atom down to answer
choice (A) or answer choice (D). But what’s different between these
two diagrams? Both of them show electrons
orbiting a central nucleus. Well, the circles in diagram (A)
are meant to represent fixed orbits for the electrons that correspond to discrete
energy levels. So this diagram is actually meant
to represent Bohr’s model of the atom, which features fixed orbits for the electrons
due to the electrons having discrete energy levels that they occupy.
So answer choice (A) isn’t what
we’re looking for either. Which leaves us with answer choice
(D), which is the correct diagram to represent Rutherford’s planetary or nuclear
model of the atom.