Illusion that shell, subshell and orbitals are the same

[avito009]

Why was I taught in high school that shell, subshells and orbitals were the same thing?

 

[Nugatory]

Why was I taught in high school that shell, subshells and orbitals were the same thing?

Because your high school teachers (almost certainly rightly) didn't think that you had the mathematical foundations needed to handle something like http://users.aber.ac.uk/ruw/teach/237/hatom.php (Picked pretty much at random, one of many thousands of explanations that you will find if you google for "Schrödinger hydrogen atom solution"), let alone the additional complications that arise in multi-electron atoms.