Article: In naming compounds, Greek prefixes are used to indicate the number of atoms present for each element. Covalent compounds are written out as molecular formulas due to the fact that each compound is a distinct, separate molecule. Covalent compounds have the first element written out completely while the second element is named with the suffix "ide." For example, diphosphorus trisulfide has a chemical formula of P2S3. Below are the prefixes for 1-10: 1: Mono- 2: Di- 3: Tri- 4: Tetra- 5: Penta- 6: Hexa- 7: Hepta- 8: Octa- 9: Nona- 10: Deca- When a compound has been written out, you must identify the elements and know their chemical symbols. The first element written is "first name" of the compound. Use the periodic table to find the chemical symbol for the element. For example: Dinitrogen hexafluoride. The first element is nitrogen and the chemical symbol for nitrogen is N. To identify the number of atoms present for each element, you simply need to look at the prefix of the element. Memorizing the Greek prefixes will help you to be able to write chemical formulas quickly without looking anything up. For example: Dinitrogen has a the prefix "di-" which means 2; therefore, there are 2 atoms of nitrogen present. Write dinitrogen as N2. The second element is the "last name" of the compound and will follow the first element. For covalent compounds, the element name will have a suffix of "-ide" instead of the normal ending of the element. For example: Dinitrogen hexafluoride. The second element is fluorine. Simply replace the "ide" ending with the actual element name. The chemical symbol for fluorine is F. As you did with the first element, identify the number of atoms present in the second element by reading the prefix. Using this prefix, write the number of atoms as a subscript to the right of the chemical symbol. For example: Hexafluoride has a prefix of "hexa-" which means 6; therefore, there are 6 atoms of fluorine present. Write hexafluoride as F6. The final chemical formula for dinitrogen hexafluoride is N2F6. When first learning chemistry, there is a lot of memorization involved. It is kind of like learning a new language. The more examples you practice with, the easier it will be to decipher chemical formulas in the future and learn the language of chemistry. Sulfur dioxide: SO2 Carbon tetrabromide: CBr4 Diphosphorus pentoxide: P2O5

What is a summary?
Memorize the prefixes for number of atoms. Write the chemical symbol for the first element. Add the number of atoms as a subscript. Write the chemical symbol for the second element. Add the number of atoms present as a subscript. Practice with some examples.