Why does the 5s sublevel fill before any electrons are added to the 4d sublevel?

Question

if you can explain this it would help me out...a lot! doesn't it have to do with something with the orbitals?

Answer 1

I think its because stabilizing the 5s orbitals requires less energy than stabilizing the 4d orbitals.

Answer 2

Please see the following site for a great explanation:

http://www.chemguide.co.uk/atoms/properties/atomorbs.html

Basically, it is because the 5s sublevel has a lower energy than the 4d sublevel. Rather than memorize the fill order, let the periodic table do the work for you. All you need to do is remember the s, p, d and f sublevel numers according to the y-axis (period number)...

s and p orbitals have same number as the period number (ie row number), d orbitals are always one number less than period number, and f orbitals are always two less than period number.

Electrons fill as the atoms sequentially appear on the periodic table...hope that makes sense!

Answer 3

The orbitals can be listed two different ways:

#1 - Listed by distance from the nucleus
everything is in order; no tricks

#2 - Listed by energy
An energy level always begins with the correct "s" and ends with the correct "p". But in between, beginning with level 4 you find
all the "d" orbitals end up one level higher and all the "f" orbitals end up 2 levels higher.

Answer 4

Not all orbitals are arranged in an ordered manner. Some orbitals of different shells overlap.

Answer 5

Its because less energy is required to fill the 5s than 4d, dont think of the numbers as 4 being less than 5 thatll just confuse you, think of it as that you always fill them in the order of going across and down the periodic table. so 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p. if my memory serves me as to the particular order, thats just from memory.