Nomenclature!!

1. Nomenclature!! (Not as complicated as youthink)

2. Whatis nomenclature? Nomenclature is a set of rules to develop systematic names for chemical compounds in chemistry. Without the knowledge of nomenclature, doing about anything in chemistry dealing with compounds, elements is that much more difficult. Here, we explain this topic clearly and provide examples as well!

3. Whatyouwillneed: • 1) Periodic table

4. 2) Common polyatomic ion sheet

5. Writingionic compound formulas:(Sodium chloride NaCl) • To go from a name to writing the compound formula, we must befamiliarwith the crossoverrule. Hereis how… • Step 1: Find the charge on each piece of the compound. • Step 2: Cross over charge #’s to quantity #’s. • Ex. Magnesium Flouride • Mg +2F -1 MgF2

6. More examples! • Beryllium phosphide Phosphorus trichloride • Be+2 P+3 P+3Cl+1 • Be3P2 PCl3 ***This crossover rule applies when dealing with ionic compounds, covalent compounds, transitional metals and polyatomic ions!!!!***

7. Naming compounds (ionic) : • Metalswith non metals “ metal, non-metal, ‘ide’” All you have to do isname the elements in the compound in order. The last element in the compound ends with“ ide”. Examples: NaCl Sodium chloride RbS  Rubidium sulfide BaN  Barium nitride LiBr  Lithium bromide MgO  Magnesium oxide The first element is a capital while the others are not. Remember to end with “ide” !!

8. Naming compounds (covalent) • Non metals with non metals: For this, you must be familiar with prefixes. To name a compound that contains two non metals, you must add a prefix in front of each element that contains more than one atom of that element. For example: NCl3  There is more than one atom of Cl, therfore we must add a prefix. Answer: Nitrogen trichloride. Remember! You must associate the prefix with the number of atoms that that element has! In the example above, there were three atoms of chloride, therefore, we added the prefix “tri’. If it was four, it would have been “tetra”. Five, “penta” etc... We did not add a prefix on the nitrogen because it only has one atom of nitrogen. If it had more than that, we would be required to add in a prefix. (See next page for more examples)

9. Examples and explanations • (“ Prefix, nonmetal, prefix, nonmetal”) • 1. PCL3  Phosphorus trichloride • Phosphorus and chloride are both nonmetals, therefore we must add prefixes. There is only ONE atom of phosphorus so instead of adding in “mono” (1 atom) we leave it as is. Chloride on the other hand, has prefix of “tri” why? Because there are THREE atoms of chloride in the compound, as a result, we add the prefix “tri” meaning three.

10. 2. P2O5 Diphosphoruspentaoxide • Phosphorus (P) and oxygen (O) are both non metals, therefore we write the compound with prefixes. In the compound we notice there are two atoms of phosphorus, how do we know this? There is a little two written next to it. So, we write phosphorus including the prefix of two. “Diphosphorus” Next, we see there are five atoms of oxygen, so we must add the prefix of five in front of oxygen, “pentaoxide” Thus we get Diphosphoruspentoxide.

11. Transitionalmetals • FORMAT: “ Transitional metal, (charge), non metal, ide” The first part of the compound must contain a transitional metal, these are located in the center of the periodic table (see periodic table) Secondly, we must add the charge of the transitional metal in brackets after we write the transitional metal. Third, we write the non metal as it is, no prefixes. Finally, we must add “ide” at the end of the non metal.

12. Transitional metals cont.. • WHY DO WE HAVE TO WRITE THE CHARGE OF THE TRANSITIONAL METAL? Transitional metals can have more than one charge! Unlike metals and non metals which mainly have one fixed charge, transitional metals can have different charges. For example lets take iron. Iron can have a charge of 2 or a charge of 3. So if we write the compound ignoring the charge we are not notified about which iron we are dealing with. Iron with charge 2 (Fe2)? or iron with charge 3 (Fe3)?

13. Examples and explanations!! • Fe2O3 Iron (3) oxide Using the CROSSOVER RULE, we know thatiron has a charge of +3 and thatoxygen has a charge of -2. So, by following the format shownpreviously, (“ Transitional metal, (charge), non metal, ide”) we write the compound as shown, Iron(3) oxide. Cu3N2  Copper(2) nitride We are using the same concept as above, we know that copper (Cu) has a charge of +2 and nitride has a charge of -3 because of the crossover rule, so we state the answer as so, Copper(2) nitride.

14. Polyatomic ions:“metal, polyatomic ion” • Polyatomic ions are usually treated as a single element because they move as a group. For example, OH , NO3 … • Ex: Silver Nitrate = Ag1+ NO3 1- • Ans: AgNO3 Using the crossover rule, we cross the charges and get our resulting answer.

15. More than one polyatomic ion is designated by using brackets and a subscript number. • Ex: Aluminum Sulphate = Al3+ SO4 2- Ans: Al2(SO4)3 Weaddbracketsaround the polyatomic ion becauseit shows us thatthereis more than one atom of thatpolyatomic ion. In this case, there are 3 atoms of Sulfate ( SO4 )

16. Bibliography • Couture, Ivan, Marie-Ève Lacombe-Harvey, and Geneviève Levasseur-Thériault. Quantum: Chemistry : Third Year of Secondary Cycle Two. Montréal: Chenelière Éducation, 2010. Print. • "Nomenclature." Http://www.files.chem.vt.edu/RVGS/ACT/ACT-home.html. N.p., n.d. Web. 10 Oct. 2012. <http://www.files.chem.vt.edu/RVGS/ACT/notes/Nomenclature.html>. • Teachers class notes, Chemistry class. (Ms. Young)