Question

How many bonds would each element like to make?

Oxygen, Nitrogen, Potassium, Carbon, and Boron

Answer 1

To know this, you need to know the number of electrons in their outer shell, so writting the electron configuration for each of them:

[O] = [He] 2s² 2p⁴   ---> 6 electrons

[C] = [He] 2s² 2p² ---> 4 electrons

[N] = [He] 2s² 2p³   ---> 5 electrons

[K] = [Ar] 3s¹   ---> 1 electron

[B] = [He] 2s² 2p¹   ---> 3 electrons.

Now for the case of K, and B, they can form 1 and 3 bonds. In the case of C, it can form up to 4 bonds. But in the case of N and O, even though they have 5 and 6 electrons, they can only form 3 and 2 bonds. This is because their last shell in the configuration is almost full, which means that they have at least one pair of electron conjugated and appealed, and the other are free. So, for that reason, and if we draw the lewis structure:

  

As you can see, they only have 2 and 3 electrons available to pair with another molecule or atom. That's why Oxigen can take 2 bonds, and nitrogen 3.

Hope this helps