Metallic compounds are made by bonding metal atoms to other metal atoms:
- Stainless steel (made of: chromium, nickel, molybdenum, silicon, aluminum)
Ionic compounds are pure substances consisting of at least one metal and one non-metal. They combine through the transferring of electrons.
3 Properties of Ionic Compounds:
- Ionic compounds are SOLID at room temperature.
- Tend to be good CONDUCTORS of electricity.
- Forms ions in solution.
When an ionic compound is melted or dissolved in water, it will conduct electricity.
When the ionic compound is dissolved in water, the metal and non-metal elements form an aqueous solution or ions. An ion is an atom or a group of atoms that have become electrically charged through the loss or gain of electrons from one atom to another.
2 Rules for naming ionic binary compounds
- The name includes both elements in the compounds, with the name of the metallic element coming first and the non-metallic element following second.
- The non-metallic element’s ending is changed to –ide.
3 Rules for using ion charges and chemical names to write formulas
- Print the metal element’s symbol with its ion charge. Next to it, print the non-metal element’s symbol with its ion charge.
- Balance the ion charges. In our example, this means that there must be two chlorine atoms with an ion charge of 1- to balance the 2+ ion charge of one calcium atom. Now you know how many atoms of each element you need to include in the formula.
- Write the formula by indicating how many atoms of each element are in it as shown. Do not include the ion charge in the formula. Place the number of atoms of each element in a subscript after the element’s symbol. If there is only one atom, no number is used.
When non-metals combine through a sharing of electrons, a pure substance called a molecule or a molecular compound is formed.
3 Properties of Molecular Compounds:
- Molecular Compounds can be SOLID, LIQUID or GAS
- Tend to be INSULATORS (poor conductors of electricity).
- Low MELTING & BOILING points because the forces between the molecules are WEAK
3 Rules for naming molecular binary compounds
- Write the entire name of the 1st element.
- Change the ending on the name of the second element to –ide.
- Use a prefix to indicate the number of each type of atom in the formula. You must do this for the all elements in the formula. Remember: the prefix mono- is never used for the first element.