Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
For a hydrogen-like ion of nuclear charge , write , where is the distance from the nucleus and . The radial parts of the wave functions of two orbitals are
A radial node is a sphere on which is zero (not counting ). Consider these orbitals in the ion ().
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Plan. Set the bracket of each function to zero, solve for , then use .
(a) and (b) and (c): the orbital. gives
Two roots, so two radial nodes (and agrees). With :
(d) The orbital. gives or . The point is not counted, so the one radial node is at ().
(e) All nodes of . One radial node and angular node (a nodal plane through the nucleus): in all, which is .
Check. A scan of each function from to finds sign changes only at and for , and only at for .
Watch out. In a hydrogen atom the same nodes would be three times farther out: every distance scales as .
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