Hi there, my name is Dr. Scott Militio and in this short under five minute video, we will cover writing the name and formula for a covalent compound. The assumption I am making is that you already know the different prefixes. We need to know the prefixes because for covalent compounds, there is a sharing of electrons and the prefixes tell us how many of each element we have in a compound. We will first go from the name to the formula. Let's look at the name carbon monoxide. When writing the formula, the first element that we come across in the name is written first, which means the element that we see second gets written second in the formula. When the first element does not have a prefix, it is assumed that there is one of them, which means for the name carbon monoxide, the formula would be CO. Now it's your turn to try writing the formula for the name di-nitrogen trioxide. Pause the video to give yourself some time. The answer is N203. Di-means 2 and tri-means 3. Before we write out the name, let's go over three rules that we need to know for naming. Number one, the element that's first in the formula is going to be written first and its name does not change. The element that is written second in the formula will be written second in the name, and the last three letters i and e will be replaced with i, d, as the ending, just as with ionic compounds. The third rule is the prefix, which will tell us the number of each element in the molecule. To determine the prefix, we look at the subscripts. Now we are ready to look at an example, CO2. The name for this would be carbon dioxide because you have one carbon and two oxygens. When we don't see a subscript after an element, the assumption is that there is one of them, and because it's the first element, we do not need to write the prefix mono in front of the word carbon. Next, if we look at the subscript on oxygen, we see that there is a two, which means that the prefix is die. Putting it all together, we get carbon dioxide. Now it is your turn with the formula CLF3. Please pause the video to give yourself some time. Did you get chlorine tri-floride? There is one chlorine, so you don't need to put mono in front of it. And for fluoride, there are three of them, which means the prefix would be tri. I hope this was helpful. Thank you for watching.