In my textbook, it claims that the maximum number of electrons that have the right to fit in any given covering is provided by 2n². This would median 2 electrons could fit in the first shell, 8 could fit in the second shell, 18 in the third shell, and 32 in the 4th shell.

However, ns was formerly taught the the maximum number of electrons in the first orbital is 2, 8 in the 2nd orbital, 8 in the 3rd shell, 18 in the fourth orbital, 18 in the 5th orbital, 32 in the sixth orbital. I am fairly sure the orbitals and also shells are the same thing.

Which of these two approaches is correct and should be supplied to discover the variety of electrons in one orbital?

I to be in high college so please try to simplify your answer and also use relatively basic terms.

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edited jan 22 "17 in ~ 9:54 Melanie Shebel♦
request Feb 20 "14 at 4:13 user3034084user3034084
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Shells and orbitals are not the same. In regards to quantum numbers, electron in different shells will have various values of primary quantum number n.

In the an initial shell (n=1), us have:

The 1s orbital

In the 2nd shell (n=2), we have:

The 2s orbitalThe 2p orbitals

In the 3rd shell (n=3), us have:

The 3s orbitalThe 3p orbitalsThe 3d orbitals

In the fourth shell (n=4), we have:

The 4s orbitalThe 4p orbitalsThe 4d orbitalsThe 4f orbitals

So one more kind that orbitals (s, p, d, f) becomes obtainable as us go come a shell with higher n. The number in front of the letter signifies which covering the orbital(s) room in. So the 7s orbital will certainly be in the 7th shell.

Now because that the various kinds the orbitalsEach type of orbital has actually a different "shape", together you have the right to see on the picture below. Friend can likewise see that:

The s-kind has only one orbitalThe p-kind has actually three orbitalsThe d-kind has 5 orbitalsThe f-kind has seven orbitals Each orbital can hold two electrons. One spin-up and one spin-down. This way that the 1s, 2s, 3s, 4s, etc., can each host two electrons due to the fact that they each have only one orbital.

The 2p, 3p, 4p, etc., can each organize six electrons because they each have three orbitals, that have the right to hold two electrons each (3*2=6).

The 3d, 4d etc., have the right to each organize ten electrons, because they each have actually five orbitals, and also each orbital can hold two electron (5*2=10).

Thus, to find the variety of electrons possible per shell

First, us look in ~ the n=1 covering (the an initial shell). That has:

The 1s orbital

An s-orbital hold 2 electrons. Therefore n=1 shell have the right to hold 2 electrons.

The n=2 (second) shell has:

The 2s orbitalThe 2p orbitals

s-orbitals have the right to hold 2 electrons, the p-orbitals have the right to hold 6 electrons. Thus, the 2nd shell have the right to have 8 electrons.

The n=3 (third) shell has:

The 3s orbitalThe 3p orbitalsThe 3d orbitals

s-orbitals have the right to hold 2 electrons, p-orbitals can hold 6, and also d-orbitals can hold 10, because that a total of 18 electrons.

Therefore, the formula \$2n^2\$ holds! What is the difference in between your 2 methods?

There"s crucial distinction in between "the number of electrons feasible in a shell" and also "the variety of valence electrons possible for a period of elements".

See more: Does A Rectangle Have Perpendicular Diagonals, Are The Diagonals Of A Rectangle Perpendicular

There"s room for \$18 \texte^-\$ in the 3rd shell: \$3s + 3p + 3d = 2 + 6 + 10 = 18\$, however, facets in the 3rd period only have actually up to 8 valence electrons. This is due to the fact that the \$3d\$-orbitals aren"t filled until we obtain to elements from the fourth period - ie. Aspects from the 3rd period don"t to fill the third shell.

The orbitals room filled so the the persons of lowest energy are filled first. The power is about like this: