Answer:
Explanation:
Wavelength gets determined by the spherical drum of electrons relative to the nucleus. The set gets into a pattern.
It is like each electron is a node, and its works best when they have the same rhythm.
One can be at 1x, or 2x, or 3x, so long as the nodes stay in synch. Here is an example where three waves want a pattern in synch - even if two are going 2x, the third (blue). That is a 2x or 3x would all fit into the blue base wave function.
