Use the following worksheets to learn how to name compounds and write formulas. If the formula is given, write down the name, and if the name is given write down the formula. Use these pages as a study guide.
As a general rule, you should know the names and symbols for elements 1-36. In addition, you should know names and symbols for all elements in Groups I and II, as well as the halogens (Group VII), noble gases (Group VIII), and some other metals used frequently. These metals include Ag (silver), Au (gold), Pb (lead), Sn (tin), and Cd (cadmium).
When naming compounds, remember the following rules:
Cation | Name | Cation | Name | Anion | Name | Anion | Name | |
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H+ | Hydrogen | Li+ | Lithium | H- | Hydride | F- | Fluoride | |
Na+ | Sodium | K+ | Potassium | Cl- | Chloride | Br- | Bromide | |
Cs+ | Cesium | Be2+ | Beryllium | I- | Iodide | O2- | Oxide | |
Mg2+ | Magnesium | Ca2+ | Calcium | S2- | Sulfide | Se2- | Selenide | |
Ba2+ | Barium | Al3+ | Aluminum | N3- | Nitride | P3- | Phosphide | |
Zn2+ | Zinc | Ag+ | Silver | As3- | Arsenide | C4- | Carbide |
Compounds containing only non-metal elements are named using Type III binary compound rules. These compounds are always neutral (not ions which have charges), and consist of only two elements (see acid naming below for compounds containing only non-metal elements, but with more than two elements. The prototypical compound is CO2, which is called carbon dioxide.
The following prefixes are used to specify the number of times an element is present in binary covalent compounds:
prefixes (1-5) | prefixes (6-10) | Examples using prefixes |
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Please note that ionic compounds (Type I & II binary compound names) never use prefixes to specify how many times an element is present. Prefixes are only used for covalent compounds formed from non-metal elements.
Acids are compounds containing an ionizable proton (H+), since an acid is a proton donor (a hydrogen atom which has lost its electron). The polyatomic anions derived from acids are named by dropping the -ic (or -ous) suffix from the acid name and adding the -ate (or -ite) suffix, respectively. Compounds containing polyatomic anions are named using the Type I or Type II naming systems described above. For example, the sodium salt of nitric acid is sodium nitrate (NaNO3). If you know the acid formula you will always get the correct anion formula and its charge, since the charge is equal to the number of ionizable hydrogen atoms in the acid, and is always negative. For example, for sulfuric acid (H2SO4), the anion is sulfate (SO42-) with a -2 charge.
Acids which do not contain oxygen (e.g., HCl, H2S, HF) are named by adding the hydro- prefix to the root name of the element, followed by the -ic suffix. HCl is hydrochloric acid, H2S is hydrosulfuric acid, and HF is hydrofluoric acid (italics added for emphasis). Anions of these acids, which contain a single element (not polyatomic), are named as a regular non-metal anion (i.e., Cl- is chloride, S2- is sulfide, and F- is fluoride).
Acid | Name | Anion | Name | Acid | Name | Anion | Name | |
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H2SO4 | sulfuric | SO42- | sulfate | HCl | hydrochloric | Cl- | chloride | |
HNO3 | nitric | NO3- | nitrate | HBr | hydrobromic | Br- | bromide | |
H3PO4 | phosphoric | PO43- | phosphate | HClO3 | chloric | ClO3- | chlorate | |
HC2H3O2 | acetic | C2H3O2- | acetate | HClO2 | chlorous | ClO2- | chlorite | |
H2SO3 | sulfurous | SO32- | sulfite | HBrO3 | bromic | BrO3- | bromate | |
HNO2 | nitrous | NO2- | nitrite | HBrO | hypobromous | BrO- | hypobromite |
Copyright © Dr. Donald L. Robertson (Modified: 11/19/2012)