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# Electron configurations for the second period

Writes out quantum numbers for all elements of the second period. Introduces Hund's rule, and connects blocks in periodic table with electron configuration. Created by Jay.

## Want to join the conversation?

• What is a "ground state condensed electron configuration" for an element? Do we use the most recent/previous noble gas and simplify the configuration accordingly?
• Ground state - most stable, all electrons are in their natural state
Condensed - use closest noble gas with a smaller atomic number (so you're correct)
For example, calcium's ground state condensed electron configuration would be [Ar]4s^2
• Why do opposite spins of electrons in same orbital make it more stable?
• Electrons have charge, and a spinning charge generates an magnetic field. If you do the right hand rule, you'll see that electrons with opposite spins have opposing magnetic fields. Essentially, these magnetic fields "cancel" each other out, thereby making it more stable than if electrons were spinning in the same direction. The magnetic force would push electrons away from each other when electrons have the same spin.
• How would one state Hund's rule in a phrase?
• If two or more orbitals of equal energy are available, electrons will occupy them singly before filling them in pairs.
• If there's only one electron in an orbital, do we assume the spin is +1/2? Does it matter?
• It doesn't really matter.
It is just a convention to assign +½ to the first electron in an orbital.
• What do the L, Ml, and the other letters stand for? Or where can I find a video to explain that concept better?
• What is the hund's rule ?
(1 vote)
• If you have multiple orbitals of the same energy (so the three p orbitals or the five d orbitals) you singly occupy each orbital with an electron of the same spin before you pair any of them up.
• why do parallel spins make an atom stable?
(1 vote)
• The greater the total spin the the more stable an atom is. If you have 3 weights on one side of a balance scale and nothing on the other side it would be more stable than if you have i weight on each side. Because it would take a greater force to push it upwards. The one with a weight on each side would be more wobbly (unstable).
• Why Be (4) is not considered as a noble gas even its structure is 1s^2 2s^2?
(1 vote)
• Because there are still three 2p orbitals to fill in the second shell