I read in a textbook that after an electron jumps to a higher energy level when supplied with high temperatures or current, they again fall back to their respective energy level by losing energy and in doing so, release photons.
First question, how does this happen with details?
I had this thought: Consider the lithium atom whose outermost subshell is the 2s. Thus atom is supplied with hundreds of degrees of temperature. The valence electron is bound to get excited. It's suppoed to jump to a higher energy level. How can it when lithium only has 2 energy levels? Furthermore, do all possible orbitals preexist in every atom in the universe? Like does lithium also have the 4p subshell but it's simply empty?