Which of the following diagrams
best represents the Balmer series of transitions?
We’re being asked about electron
energy level transitions and specifically to choose which of the four diagrams
shows the Balmer series of transitions. Before we can choose the right
diagram, we should remind ourselves about how electron transition series are
First of all, only transitions
where an electron loses energy, or goes from a higher energy level to a lower
one, belong to named series such as the Balmer series. Transitions where electrons gain
energy and go up to higher energy levels are not included in these named
series. This allows us to eliminate
answer options (A) and (C).
Importantly, it’s the energy
level that the electron transitions down to that determines which series the
transition is a part of. It does not matter which energy
level the electron started from. Electron transitions down to
level 1 are part of the Lyman series. Transitions down to level 2 are
part of the Balmer series. And transitions down to level 3
are known as the Paschen series.
When we look at the remaining
answer options, we see that option (D) shows transitions to the third energy
level, which is the Paschen series. Option (B) shows transitions
down to the second energy level, which is the Balmer series we are looking
for. Our final answer is option