Read the article and answer the following questions. Ionic Bonding Why did it require two sodium atoms to complete the Na2O formula unit? Na has +2 charge and O has -1 charge. Na has +1 charge and O has -2 charge. Na has -2 charge and O has +1 charge.

In what way do investigations build scientific knowledge? the results of investigations lead to questions that cannot be tested. they reflect the opinions and social values of scientists, ensuring valid information. the results of investigations lead to new questions, which lead to new investigations. they are not influenced by the research of earlier scientists, so they are able to address gaps in understanding.i