How many more valence electrons does chlorine need to satisfy the octet rule? Chlorine is in group 17

May someone me with these science questions

Complete each row of the table below by filling in the missing prefix or missing exponent.

Predict the relative bond lengths of the three carbon-oxygen bonds in the carbonate ion (co2−3). what would you expect the charge to be on each oxygen? match the words in the left column to the appropriate blanks in the sentences on the right. make certain each sentence is complete before submitting your answer.