How can I find valence electrons in polyatomic ions?

1 Answer

To determine the number of electrons in polyatomic ions you will need to determine the number of valence electron for each element present in the ion and make a correction given the charge of the ion.

Example 1:
#OH^-# =
Oxygen has 6 valence electrons
Hydrogen has 1 valence electron
Need 1 more to get the charge of -1
Total number = 8

Example 2:
#NH_4^+# =
Nitrogen has 5 valence electrons
Hydrogen has 1 valence electron x 4 (because you have 4 atoms of H)
Need to remove 1 electron to get +1 charge of the ion
Total number = 8

Here are some videos to review to help with this concept.

Video from: Noel Pauller

Video from: Noel Pauller

Hope this helps!