i had a question about electrong moving to a higher level of energy. When they do move to higher level energy do they get closer to nucie or do they move further from the nuclie (ie when forming a Photon.) When sodium makes a yellow light would the wave length get smaller if an electron from a diffrent shell moves or does it get bigger? i am doing year 11 physic and i asked this question to my teacher and he said that he wants me to find it out. I know that he knew the answer but he wants me to find the answer.