Which of the following is the electron configuration of an electrically neutral atom of argon (Ar)?

Question

majesticgalaxy · Answer

A. 1s2 2s2 2p5
B. 1s2 2s2 2p6 3s2 3s6
C. 1s2 2s1
D. 1s2 3d10 4f7

jamierox4ev3r · Answer

A good way to find this is to count the electrons that Argon has in total

jamierox4ev3r · Answer

@MajesticGalaxy

majesticgalaxy · Answer

Okay, I am not too familiar with orbitals so someone reffered me to you

majesticgalaxy · Answer

is this question hard to solve?

jamierox4ev3r · Answer

That would be my roommate, Brittany.

So here, we want to see what the atomic number of Argon is. This can be found on a periodic table. Can you tell me what it is?

jamierox4ev3r · Answer

And this can be difficult to grasp at first, but it gets easier once you understand

majesticgalaxy · Answer

argon is Ar on the periodic table right?

jamierox4ev3r · Answer

yup!

majesticgalaxy · Answer

what I don't understand is how to find out the electron configuration, if I know that then solving this question would be way easier

jamierox4ev3r · Answer

There's an easy way to do this

s orbitals always have 2 electrons WHEN FULL, so you will always see $2s^2$ and never $2s^3$
p orbitals always have 6 electrons WHEN FULL, so you will always see $2p^6$ and never $2p^6$
d orbitals always have 10 electrons WHEN FULL, so you will always see $3d^{10}$ and never $3d^{11}$

jamierox4ev3r · Answer

Also, here's a nice picture that tells you the order of the Afbau principle

jamierox4ev3r · Answer

|dw:1478831825897:dw|

jamierox4ev3r · Answer

See how the s only has one line, and p has 3 lines, and d has 5 lines, etc?

one line correlates to 2 electrons, and the order so far seems to be $1s^2, 2s^2, 2p^6, 3s^2...$

majesticgalaxy · Answer

Oh ya

jamierox4ev3r · Answer

yup! And here's a diagram that will help you remember the order : |dw:1478831955905:dw|

majesticgalaxy · Answer

Oh okay that makes it sooo much easier

jamierox4ev3r · Answer

yeah? :)

jamierox4ev3r · Answer

Glad I could be of help!

majesticgalaxy · Answer

how would we incorprate this to the answer choices though?

jamierox4ev3r · Answer

Let's rule out answer choices together

majesticgalaxy · Answer

okay

jamierox4ev3r · Answer

So A...do you think this could be the answer?

majesticgalaxy · Answer

Nope I don't think so

brittanyrolfe · Answer

Jamierox4ev3r has to restart her computer really fast. I hooked you up on this question in the bio, if you want to look at it after this. But she will be right back :)

majesticgalaxy · Answer

Oh okay, no worries i'll wait

majesticgalaxy · Answer

Wait nevermind I gotta go already, thanks so much for your help I really appreciate it :)

jamierox4ev3r · Answer

oh okay! Do you understand why?

majesticgalaxy · Answer

Yes I saved the images so I can look at them later and (Hopefully!) remember them lol

majesticgalaxy · Answer

Okay bye :)

jamierox4ev3r · Answer

haha alright!