Chemical Nomenclature

Oct 2, 2009 at 8:05 PM | Posted by lacheeeks
In today's class, we discussed atoms, ions, elements and compounds as well as how to name ionic binary compounds.


Things to know:
  • An element is a substance that cannot be separated into simpler substances by a chemical change.
  • A compound is a substance that contains two or more elements combined in a fixed proportion.
  • A hydrate is any class of compound containing water. The procedure of how to name hydrates is in the following post.
  • A multivalent element has more than one ionic charge. In the periodic table, the most common ionic charge will be placed first for the element.
  • An atom is the smallest particle of an element that retains the chemical identity of the element; made up of negatively charged electrons, positively charged protons, and uncharged neutrons. Its structure:
  • An ion is an atom or group of atoms that has a positive or negative charge because it has lost or gained electrons.
  • The difference between an atom and an ion: an ion is an atom or group of atoms, normally electrically neutral, that has lost or gained one or more electrons.
  • An ion consisting of a single atom is called a monatomic ion, and an ion consisting of multiple atoms is called a polyatomic ion. Larger ions containing many atoms are called molecular ions.
Remember, in chemical formulas, the ion charge is indicated by a superscript (a small number to the top right), and the number of ions is indicated by a subscript (a small number to the bottom right).

How to name ions:
  • for metals, use the name of the element and write the ion charge
  • for non-metals, remove the original ending and add 'ide' and write the ion charge
  • for polyatomic ions, there are special names



How to name binary ionic compounds:
  1. Write the formula for the cation first, and the formula for the anion.
  2. Criss-cross the charges, moving the numbers below.
  3. Reduce the ion numbers to the lowest common multiples. Note: You do not need to write the subscript '1' or the ionic charges.

Naming polyatomic compounds is quite similar to that of naming binary ionic compounds. The steps are exactly the same. The only difference is that there will be more than one element written in one ion. Don't get confused!

How to name multivalent ions:
  • the more common charge will be placed on top in the periodic table
  • remember to use roman numerals in parentheses to show the charge
The Periodic Table of Elements to help you name the compounds, which includes SOME of the elements' ionic charges:



Additional help on how to name ionic compounds:

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1 Responses to Chemical Nomenclature

  1. Mr. Doktor Says:
    Posted on October 6, 2009 at 8:38 AM

    I'm glad you mentioned ions. Most people forgot to. Do you remember how to name ions? Whats the difference between an ion and an atom?

    You did not include enough of how to name compounds. Make sureyou explain the differences between writing formulas and naming multivalent and polyatomic ionic compounds as well as hydrates.

    Other than those things, it looks good so far.