How many p-orbitals are occupied in a K atom?

1 Answer
Jan 28, 2015

Potassium (K) is located in group 1, period 4 of the periodic table and has an atomic number of 19.

Since you're dealing with a neutral atom, the number of electrons K has must equal 19. You could determine how many p-orbitals are occupied in a K atom by writing its electron configuration

K:1s22s22p63s23p64s1

As you can see, the 2p and 3p sublevels each hold six electrons, which means that they are completely occupied. Since every p sublevel has a total of three p-orbitals - px, py, and pz - the number of p-orbitals occupied in a K atom is equal to 6 - 3 p-orbitals on the 2p sublevel and 3 p-orbitals on the 3p sublevel.

A faster way to figuring out how many p-orbitals are occupied in a K atom is by looking at the periodic table. The periodic table is split into blocks, as you can see here

http://imgarcade.com/1/spdf-periodic-table/http://imgarcade.com/1/spdf-periodic-table/

So, all you have to do is read the periodic table from left to right across each period - much like you would a sentence - until you get to potassium.

If you do this, you'll notice that you've passed two p sublevels: the one that starts at B and ends at Ne - the 2p sublevel - and the one that starts at Al and ends at Ar - the 3p sublevel. Once again, the conclusion is that K has 6 p-orbitals which hold 12 of its 19 electrons.

http://www.chemguide.co.uk/http://www.chemguide.co.uk/