Chemistry Review

[admiral_ju00]

Hoping I wouldn't sound like a complete dumbass, or even at the rist of it......

 

I'm trying to review my Chem and I forgot some of the basics and it is really pissing me off.

 

I know that electrons want to ocupy the lowest level shell, and if they need to move to the next energy shell that excerts energy, etc.

 

So, that said, taking Ca and breaking it down to it's electron configuration, which is the correct answer:

 

 

[math]1s^2 2s^2 2p^6 3s^2 3p^6 4s^2[/math]

 

or

 

[math]1s^2 2s^2 2p^6 3s^2 3p^6 3d^2[/math]

 

If it's the 1st one, why would the 2 electrons jump to [math]4s^2[/math]?

Isn't the next lower lvl subshell is the [math]3d^2[/math]?

Or do these 2 electrons go to [math]4s^2[/math] because the [math]3d^x[/math] is incomplete while [math]4s^2[/math] is. ???

[YT2095]

4s2 is Ca.

 

or Ar,4s1,4s2 (shorthand).

[admiral_ju00]

I'm still failing to see this.

Are you saying that when you break elements into their electron configuration, you use Ar as a base(since it has 18 electrons) and then build on from there?

[Skye]

Yeah. It's normal to abbreviate the larger atoms by substituting the symbol for the previous noble gas for all the electron configurations up to that point. The electrons left over are those in the outer shell, the ones that can participate in chemical reactions.