Video Transcript
The graph shows the probability of
finding the electron at a distance from the nucleus in the 1s orbital of an atom of
hydrogen. At what approximate distance is the
electron most likely to be found from the nucleus?
Here is the graph. The probability of finding the
electron is on the 𝑦-axis, and its distance from the nucleus is on the 𝑥-axis. Without units for the probability
axis, we can assume we’re dealing with relative probability. So points that are higher up the
𝑦-axis have a higher probability than points that are lower. The question also tells us we’re
dealing with an electron in the 1s orbital of an atom of hydrogen. An atom of hydrogen has the
electron configuration 1s1. s-type orbitals are spherical. This means the probability of
finding an electron doesn’t vary depending on which angle you’re pointing out. It’s only the distance from the
nucleus that matters.
We need to find the approximate
distance from the nucleus of this electron that’s most likely. The most likely event is the one
with the highest relative probability. So we need to find the highest
point of this curve and then draw down to the 𝑥-axis to find the distance. The highest point on this curve is
here. This corresponds with a distance
from the nucleus the 50 picometers. The question is only asking for the
approximate distance. But to my eye, that peak is bang on
the line of 50 picometers, so we can be comfortable that 50 picometers is the
correct answer. What this means is if you were to
check where the electron was in a 1s orbital of a hydrogen atom, more times than any
other it would be in about 50 picometers.
