So, you know that atoms have electrons. But how are they organized around the atom? While we don\'t know their exact positions and speeds, we do know their energies and they are very organized. By now, you\'ve probably seen stuff like 1s1, 1s22s22p3, etc. Each orbital has a name like X typey. X is the energy level. These correspond roughly to the rows of the periodic table. Notice how rows have more elements as the energy level increases. This just means there is room for more elements. \"type\" is the subshell. There are 4 you will encounter: s, p, d, and f. Every energy level (X) has an s subshell. For X2, every energy level has a p orbital. For X3, every energy level has a d, and for X4, every energy level has an f. The s subshell can hold a max of 2 electrons. The p can hold 6, the d can hold 10, and the f can hold 14. The electrons in these levels aren\'t spread around haphazardly either. Within these subshells are the orbitals. The s has 1, the p has 3, the d has 5, and f has 7. Each orbital can hold a maximum of two electrons. The number of electrons is given by the \"y\" in the X typey notation. There is a rule for filling though: Since all the orbitals are the same energy, the electrons prefer to occupy empty orbitals before pairing up with another electron (Hund\'s rule). Think of it like sitting on a bus - you\'d take an empty seat before sitting next to someone. Electrons are like that too. So, for an element like Calcium, the subshells would be 1s2 2s2 2p63s23p64s2 See the progression here? Every subshell is filled up to the 4s subshell. Sometimes this is written as [Ar]4s2. The reason for this is that Argon (Ar) is the highest noble gas before Calcium, so you can abbreviate the subshells before by saying they\'re the same as Argon. Now there\'s one more caveat. Remember how I said the 3rd energy level has a d subshell? Well, it turns out that this 3d subshell has more energy than the 4s subshell! So, it appears on the 4th row, despite having an energy level of 3. So, the orbital configuration for Krypton is: 1s2 2s2 2p63s23p64s23d104p6 (Some sources put the 3d before the 4s, but this way makes more sense) See how it goes from 4s to 3d and then to 4p? Yeah, the 3d orbital creeps ahead a little bit. And lastly, the last two rows at the bottom, underneath the rest? Those are the f orbitals. They could be in the rest of the chart, but it would be really long and would have a lot of white space, so they are moved to the bottom for purely aesthetic reasons. So, that\'s about all there is to know. Please rate! :-) Solution So, you know that atoms have electrons. But how are they organized around the atom? While we don\'t know their exact positions and speeds, we do know their energies and they are very organized. By now, you\'ve probably seen stuff like 1s1, 1s22s22p3, etc. Each orbital has a name like X typey. X is the energy level. These correspond roughly to the rows of the periodic table. Notice how rows have more elements as the e.

1. So, you know that atoms have electrons. But how are they organized around the atom? While we
don't know their exact positions and speeds, we do know their energies and they are very
organized.
By now, you've probably seen stuff like 1s1, 1s22s22p3, etc. Each orbital has a name like X
typey. X is the energy level. These correspond roughly to the rows of the periodic table. Notice
how rows have more elements as the energy level increases. This just means there is room for
more elements. "type" is the subshell. There are 4 you will encounter: s, p, d, and f. Every
energy level (X) has an s subshell. For X2, every energy level has a p orbital. For X3, every
energy level has a d, and for X4, every energy level has an f. The s subshell can hold a max of 2
electrons. The p can hold 6, the d can hold 10, and the f can hold 14. The electrons in these levels
aren't spread around haphazardly either. Within these subshells are the orbitals. The s has 1, the
p has 3, the d has 5, and f has 7. Each orbital can hold a maximum of two electrons. The number
of electrons is given by the "y" in the X typey notation. There is a rule for filling though: Since
all the orbitals are the same energy, the electrons prefer to occupy empty orbitals before pairing
up with another electron (Hund's rule). Think of it like sitting on a bus - you'd take an empty
seat before sitting next to someone. Electrons are like that too.
So, for an element like Calcium, the subshells would be
1s2 2s2 2p63s23p64s2
See the progression here? Every subshell is filled up to the 4s subshell. Sometimes this is written
as [Ar]4s2. The reason for this is that Argon (Ar) is the highest noble gas before Calcium, so you
can abbreviate the subshells before by saying they're the same as Argon.
Now there's one more caveat. Remember how I said the 3rd energy level has a d subshell? Well,
it turns out that this 3d subshell has more energy than the 4s subshell! So, it appears on the 4th
row, despite having an energy level of 3. So, the orbital configuration for Krypton is:
1s2 2s2 2p63s23p64s23d104p6
(Some sources put the 3d before the 4s, but this way makes more sense)
See how it goes from 4s to 3d and then to 4p? Yeah, the 3d orbital creeps ahead a little bit.
And lastly, the last two rows at the bottom, underneath the rest? Those are the f orbitals. They
could be in the rest of the chart, but it would be really long and would have a lot of white space,
so they are moved to the bottom for purely aesthetic reasons.
So, that's about all there is to know. Please rate! :-)
Solution

2. So, you know that atoms have electrons. But how are they organized around the atom? While we
don't know their exact positions and speeds, we do know their energies and they are very
organized.
By now, you've probably seen stuff like 1s1, 1s22s22p3, etc. Each orbital has a name like X
typey. X is the energy level. These correspond roughly to the rows of the periodic table. Notice
how rows have more elements as the energy level increases. This just means there is room for
more elements. "type" is the subshell. There are 4 you will encounter: s, p, d, and f. Every
energy level (X) has an s subshell. For X2, every energy level has a p orbital. For X3, every
energy level has a d, and for X4, every energy level has an f. The s subshell can hold a max of 2
electrons. The p can hold 6, the d can hold 10, and the f can hold 14. The electrons in these levels
aren't spread around haphazardly either. Within these subshells are the orbitals. The s has 1, the
p has 3, the d has 5, and f has 7. Each orbital can hold a maximum of two electrons. The number
of electrons is given by the "y" in the X typey notation. There is a rule for filling though: Since
all the orbitals are the same energy, the electrons prefer to occupy empty orbitals before pairing
up with another electron (Hund's rule). Think of it like sitting on a bus - you'd take an empty
seat before sitting next to someone. Electrons are like that too.
So, for an element like Calcium, the subshells would be
1s2 2s2 2p63s23p64s2
See the progression here? Every subshell is filled up to the 4s subshell. Sometimes this is written
as [Ar]4s2. The reason for this is that Argon (Ar) is the highest noble gas before Calcium, so you
can abbreviate the subshells before by saying they're the same as Argon.
Now there's one more caveat. Remember how I said the 3rd energy level has a d subshell? Well,
it turns out that this 3d subshell has more energy than the 4s subshell! So, it appears on the 4th
row, despite having an energy level of 3. So, the orbital configuration for Krypton is:
1s2 2s2 2p63s23p64s23d104p6
(Some sources put the 3d before the 4s, but this way makes more sense)
See how it goes from 4s to 3d and then to 4p? Yeah, the 3d orbital creeps ahead a little bit.
And lastly, the last two rows at the bottom, underneath the rest? Those are the f orbitals. They
could be in the rest of the chart, but it would be really long and would have a lot of white space,
so they are moved to the bottom for purely aesthetic reasons.
So, that's about all there is to know. Please rate! :-)