1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Mutiple Valences, Ionic compounds and Transition metals.

  1. Jul 15, 2011 #1
    So i was doing my school work earlier and i had trouble wrapping my head around this particular topic, even though i was able to finish all of it correctly, i want to make sure it sinks it well so i once again decided to approach these forums :)

    We were naming Ionic compounds, specifically with transition metals in them, and i learned that transition metals have different valences, for example Iron (Fe) has a valence of either +2 or +3...

    So depending on which valence the Iron has we use roman numerals to write them

    Iron (III)bla bla(not a real element)

    Also sometimes the valences are cancelled out before they are written in forumla form

    for example for arguments sake make up a random element, that has a valence of 4, and another element has a valence of 2

    here, they factor out the numbers and one of the elements is written with a 2(since 2 goes into 4 2 times) and one is written with a 1(invisible)

    so the compound is blabla2(bla)--->second element in the compound

    My question is, all that stuff is it accurate? or am i wrong about the concept of this?

    (sorry i couldnt be clearer, just writing this as it comes to me)

    in other words does it make sense?
    Last edited: Jul 15, 2011
  2. jcsd
  3. Jul 15, 2011 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

    Yes, for ionic compounds any common factors are taken out of the subscripts, in other words the formula is reduced "to lowest terms".

    For molecular compounds, the subscripts represent the actual number of each type of atom in a molecule. (Unless it is specifically said that they want the empirical formula.)
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook