Does any one know an easier way to do electron configurations? Also what is meant by ''weighted average''?

Question

I'm working on a table for my Chem class and can't quite get it right, any good pointers are welcome : )

Answer 1

I had a really hard time memorizing shell orders in chemistry, so I made this chart. It's infinitely easier than just memorizing it straight up. Just remember: S shells hold 2 electrons, P shells hold 6 [4 more than S], D shells hold 10[Four more than P], and F shells hold 14 [Four more than D]. (You probably won't have to go beyond P or MAYBE D though.)

Read this chart from top to bottom and from right to left.

__
|1s|
|2s|__
|3s|2p|
|4s|3p|__
|5s|4p|3d|
|6s|5p|4d|__
|7s|6p|4d|4f|

Again, you probably won't go beyond the D shells, so don't worry about memorizing everything. I hope this helps you! I know it helped me a lot.

For more information on electron configuration than you could ever want, check out wikipedia: http://en.wikipedia.org/wiki/Electron_configuration

If you think you understand it though, don't click that link. There's a lot of information there, more than you need to know, and it will just confuse you or make you think you don't understand it. It's really very simple. Good luck with your project!

Answer 2

There is no easy way to do electron configurations. Just keep grinding it out.

Weighted average are often use when you have two or more averages that you want to combine, but they aren't the same, so you can't just average the averages and get what you want.

example

you have 3 cars : bug, suv, semi

the bug averages 30 mpg, and you have driven it 1000 miles this month

the suv averages 15 mpg, and you have driven it 10 miles this month

the semi averages 8 mpg, and you have driven it 1 mile this month

what is the average gas mileage of these cars? well, if you want to know the plain average of the averages, it is (30+15+8)/3 or about 18.

if you want to know your average gas mileage this month, you need WEIGHTED averages to reflect the fact that you didn't drive them all equally

so, you weight them by the amount of miles

that is ((30*1000)+(15*10)+(8*1))/1011 = 29.8

because you mostly drove the bug, you pretty much got bug mileage this month, which is probably why you drove it

Answer 3

Ok. I'm going to type exactly what my PCAT book has for you for the electron configurations. It should be really helpful if you have a slight clue of what you are doing.

"For a given atom or ion, the pattern by which subshells are filled and the number of electrons within each principal leveland subshell are designated by an ELECTRON CONFIGURATION. In electron configuration notation, the first number denotes the principal enery level, the letter designates the subshell, and the superscript gives the number of electrons in that subshell. For example, 2p^4 indicates that there are 4 electrons in the second (p) subshell of the second principal energy level.

When writing the electron configuration of an atom, it is necessary to remember the order in which subshells are filled. Subshells are filled from lowest to highest energy, and each subshell will fill completely before electron begin to enter the next one. The (n+l) rule is used to rank subshells by increasing energy. This rule states that the lower the values of the first and second quantum numbers, the lower the energy of the subshell. If two subshells possess the same (n+l) value, the subshell with the lower "n" value has a lower energy and will fill first. The order in which the subshells fill is as follows:

1s, 2s, 2p, 3s, 3p, 2s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, 7p.

To determine which subshells are filled, you must know the number of electrons in the atom. In the case of uncharge atoms, the number of electrons equals the atomic number. If the atom is charged, the number of electrons is equal to the atomic number plus the extra electrons if the atom is negative, or the atomic number minus the elctrons is possitive."

That is how you figure out electron configurations. I'm not sure if you need to draw orbital diagrams or just writing out what they are. If you need to draw orbital diagrams, you need to apply Hund's rule. If you just need to know the order of which electrons are added to orbitals in the periodic table, they are as follows:
Columns 1, 2, and Helium= "s" (these are called the Representitive s-block elements)
Columns 9 through 12 = "d" (these are also called the transition metals)
Columns 13 - 18 = "p" (these are the representative p-block elements)
rows columns of 14 colum elements at the bottom of the periodic table have valence "f" orbitals. (these are the f-block metals)

If you can picutre what I listed up there, you basically know the configurations for the elements throughout the table, and you can name or draw basically any of them. Hope I helped!

Answer 4

Unfortunatly electron configurations are a pain in the butt. If you are having to write them out there is a short hand method. This is called "noble gas configuration".
1st: find the element that you are writing the configuration for.
2nd: find the first noble gas that is lower in atomic # than the element you are looking at.
3rd: instead of writing out all of the orbitals put the noble gas abbeviation in brackets and postscript of a full valence then the remaining valence shells till you get to your element.

I.E.

electron config for Copper (Cu)

long way: 1s2 2s2 2p6 3s2 3p6 4s2 3d9
short way: [Ar] 4s2 3d9

As for weighted average. This has to do with the fact that all elements do not have exactly the same number of neutrons and protons. I am sure that you have heard of C14, carbon 14, this element is exactly the same as carbon 12 except it has two more neutrons than regular carbon. C14 occurs naturally and is found in most things on earth. The weighted average part is that C14 has but a fraction of the abundancy of C12. So for scientist to represent the atomic mass of an element, by the way these anomalies are called isotopes, they have to account for all the different forms of the element: so think of it like there are 1000 atoms of Carbon in a jar 997 of them ar C12 and 3 of them are C14.

997 x 12 =11964 3 x 14 = 42

(11964 + 42)/1000 = 12006/1000= 12.006

This is basically saying that because of the natual abundance of C14 in the world that the atomic mass on average for all the carbon in the world is going to be 12.006 and not 12.000

Answer 5

Don't know about electrons.
Weighted average means some things are counted for more than others.
So if you and 3 friends voted on which movie to go to... and it was 2 versus 2, then it would be a tie, unweighted. If you were the leader and your vote counted for more than the others (say for 2 votes instead of one), then the average would between you and your friend would be 1+2/2 =1.5 versus the average of the other two people 1+1/2 =1