Question

According to the Bohr- Bury concept , the maximum number of electrons present in an orbit of an atom is ---- 2n 2 , where n is the number of shell or orbit So , in K shell there are 2 * (1) 2 = 2 electrons and similarly L shell can accomodate8 electrons and M shell can have 18 electrons ...and so...on..... My question is if 'M ​'​ shell can have maximum 18 electrons , then why while writng the electronic configuration we stop at 8 and for next electron we jump off to another orbit...??

Answer 1

your answer is right that we use the formula of 2nsquare in putting electrons into orbits but the last orbit should contain only 8electrons or less than that so while doing electronic configuration we cant put more than 8 electrons in last shell see an example no of electrons in calcium is 20so its electronic configuration will be2,8,8,2 we cant write like this 2,8,10 because this will be wrong as last shell cant contain more than 8electrons.