Draw electron dot diagrams for the following elements and ions. a. ca b. k+ c. o2- d. o

Here's what I get  

Explanation:

See the image below.

Ca is in Group 2. It has two valence electrons.

K is in Group 1. It has one valence electron. The + sign shows that it has lost the electron, so there are no dots around the symbol.

O is in Group 16. It has six valence electrons. The 2- shows that it has gained two electrons, for a total of eight, so there are eight dots around the symbol,

The electron dot diagram for O shows six dots for its valence electrons.