## Electron Configuration

605110118
Posts: 75
Joined: Wed Sep 18, 2019 12:21 am

### Electron Configuration

In terms of electron configuration/orbitals, I understand where the s,p,d,and f come from but what defines the number that pretenses it. For example 1s, 2d or 3p, what do those numbers represent and how does one distinguish or assign an element as occupying 2p vs 3p?

Ashley Kao 1H
Posts: 50
Joined: Thu Jul 25, 2019 12:16 am

### Re: Electron Configuration

I believe that the varying numbers can almost be seen as the round of that level. We understand that the orbitals are arranged into s, p, d, and f around the atomic nucleus. However, as we progress further away from the center of the atom, these levels repeat themselves in the same order. Thus, orbitals s, p, d, and f will be accompanied with a number to show which s, p, d, or f orbital it is. Further, when we look at 2p compared to 3p, we can understand that the electrons in 2p are closer to the center than those in 3p.

ABombino_2J
Posts: 102
Joined: Thu Jul 11, 2019 12:15 am

### Re: Electron Configuration

You need to memorize it based on where the element shows up on the periodic table. The first S orbital begins with 1. The first P orbital starts with 2. The first D orbital starts with 3. The first F orbital starts with 4. For each row you go down on the periodic table these numbers increase by 1.

Chem_Mod
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### Re: Electron Configuration

The number that precedes the orbital shape (s,p,d,f) is the principal quantum number, or energy level. The first energy level is n=1, the second energy level is n=2, etc. The higher the energy level, the greater the energy of its electrons. The principal quantum number also determines the orbital shapes and numbers in an energy level. It also corresponds to the periods in the periodic table: for example, elements in the third period can have electrons in orbitals up to the 3rd energy level. Dr. Lavelle will elaborate more on quantum numbers and electron configurations this week and next.

Kyla Grunden 1L
Posts: 46
Joined: Sat Sep 07, 2019 12:16 am

### Re: Electron Configuration

Remember that s, p, d, and f orbitals are different types of bonds, s orbitals use sigma bonding, p orbitals use pi bonding, and so on. The numbers represent the energy level of the orbital. Within each energy level, there are multiple orbitals.

To assign an electron to an orbital and energy level, remember that the lowest energy orbital fills first (NOT the lowest energy level). This can be confusing because not every type of orbital bond's energy level starts at 1. For example d orbitals start at the third energy level. This is why electrons fill up in this order: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, and so on.

I've linked a cheat sheet that shows the order electrons fill because it can be so confusing!

Hope this helps!