Question

How do I use the aufbau principle to predict the electron configuration of carbon?

Answer 1

See the answer below...

Explanation:

The electronic configuration of carbon using the aufbau principle is `color(red)(1"s"^2 2"s"^2 2"p"^2`. It is in the p-block as shown:

Carbon has `color(red)(6` electrons in total. `2` of them exist in the first energy level `color(brown)((n=1))` and the remaining `color(red)(4` electrons exist in the second energy level `color(brown)((n=2))`.

We know that for first principal quantum number`color(red)((n=1))`, the electron lies in the `color(red)("s orbital"` `(l=0)` and for second principal quantum number the electron lies in `color(red)("s orbital")` `(l=0)` and `color(red)("p orbital")(l=1)` gradually by the aufbau principle.

`underbrace(ul(color(white)(uarr darr))" "ul(color(white)(uarr darr))" "ul(color(white)(uarr darr)))_(2p)`

`ul(color(white)(uarr darr))`
`2s`

`ul(color(white)(uarr darr))`
`1s`

Now,each orbital fills by `color(red)("2 electrons"`. To fill the orbital we consider `color(red)("Hund's Rule"`:

No electron spin pairing starts in any of the orbitals of approximately equal energy until the subshell is half-filled.

`underbrace(ul(uarrcolor(white)(darr))" "ul(uarrcolor(white)(darr))" "ul(color(white)(uarr darr)))_(2p)`

`ul(uarr darr)`
`2s`

`ul(uarr darr)`
`1s`