) and
negative ions (anions).
Table of Common Molecular Compounds. These compounds are very common and have names that don't follow the usual naming conventions for molecular compounds. They should be memorized.
| Name | Formula | Name | Formula |
| ammonia | NH3 | methane | CH4 |
| carbon dioxide | CO2 | nitrous oxide | N2O |
| carbon monoxide | CO | nitric oxide | NO |
| hydrazine | N2H4 | sulfur dioxide | SO2 |
| hydrogen peroxide | H2O2 | water | H2O |
| hydrogen sulfide | H2S | ||
) and
negative ions (anions).
 electron acceptor (Cl) meets electron donor (Na) |
electron jumps from Na to Cl
|
 ions attract to form neutral pair |
 an ion pair |
 an ion cluster |
 an ion crystal |
Quiz| Molecular compounds | Ionic compounds | |
| smallest particles | molecules | cations and anions |
| origin of bonding | electron sharing | electron transfer |
| forces between particles | strong bonds between atoms weak attractions between molecules |
strong attractions between anions and cations strong repulsions between ions of like charge |
| elements present | close on the periodic table | widely separated on the periodic table |
| metallic elements present | rarely | usually |
| electrical conductivity | poor | good, when melted or dissolved |
| state at room temperature | solid, liquid, or gas | solid |
| melting and boiling points | lower | higher |
| other names | covalent compounds | salts |
Copyright © 1997-2005 by Fred Senese
Comments & questions to fsenese@frostburg.edu
Last Revised 06/11/07.URL: http://antoine.frostburg.edu/chem/senese/101/compounds/print-ionicvscovalent.shtml