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Homework Help: Charges of Ions in Periodic Table

  1. Jan 19, 2005 #1
    Hello all

    Is there any good way to memorize the charges of elements in the periodic table?

  2. jcsd
  3. Jan 19, 2005 #2
    Yes.... the elements in the 1st column form +1 ions
    " " " " 2nd " form +2 ions

    The transition metals are tricky but I wouldn't expect you'd have to know those in an elementaary class

    All the elements on the right side of the table form (-) ions except the noble gases
    The elements in column 7 form - 1 ions (starting with Fluorine )
    " " " " 6 form - 2 ions (starting with Oxygen )
    " " " " 5 form - 3 ions (starting with Nitrogen )

    Colum 4 (sarting with Carbon ) doesn't ionize
    and for colum 3 Boron and Aluminum form +3 ions

    By colums Im really reffereing to the families which are usually given in Roman Numerals
    Last edited: Jan 19, 2005
  4. Jan 19, 2005 #3


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    Absolutely. Take your periodic table and starting on top of Hydrogen (the alkaline family) write 1+. Then for each family continue, alkali earth metals 2+ *skip the transition metals, most people refer to a book for the charge of a specific metal because they have many different charges. So now on top of Boron you have 3+, Carbon 4+4-, Nitrogen 3-, until Helium zero. Every element downward (same family) has the same charge, but different valence number. The valence electron number is given by going downward by period. For example H, and He =1 valence electron. Soon enough, have a picture of the periodic table in your head, you begin to automatically know the charge.
    Last edited: Jan 19, 2005
  5. Jan 19, 2005 #4


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    If I had a nickel for everytime that happened... :rofl:
  6. Jan 19, 2005 #5
    thanks a lot guys.

    so from Boron to the end it goes: [tex] 3^+ , 4^+ 4^-, 3^-, 2^-, 1^- [/tex]?

    PS: What are the basic rules in naming inorganic compounds?
  7. Jan 19, 2005 #6


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    Organic compound? That Im not, sure usually they just give it a name like sulfuric acid or citric acid. But for binary, or radical compounds it goes as follows.
    Let's say you have Mg and N:
    You cross the charges over and get,
    You now have Magnesium Nitride
    When a metal and a non-metal react, you dont need to use prefixes, but lets say Nitogen and oxygen, once the cross is done you have
    Now you have dinitrogen trioxide.

    *Maybe you already knew this... :rolleyes:
  8. Jan 19, 2005 #7
    NO ... be carefull
    The column containing Carbon doesn't ionize (there's no such thing as +4 or -4 ion)
    The column containing Nitrogen then starts with -3
    The column all the way to the right (the noble gasses) doesn't ionize they are stable => they never ever ever ionize ( at least for the sake of an elementary chemistry class which extends to first two years undergrad )

    for ionic compounds, just add the suffix -ide to the end of the non-metal
    for covalent compounds you need to use the rules about prefixes (you can find these online, and they should be in your book )
    Last edited: Jan 19, 2005
  9. Jan 19, 2005 #8
    are you sure about the [tex] 4^+, 4^- [/tex] ? Also is there any good device for memorizing the solubility rules?

  10. Jan 19, 2005 #9
    Positive about the +4 -4, the reason that atoms become ions is because they want to obtain an octet of valence electrons. For metals( which typically have 1,2,or 3 valence electrons as atoms) it is much easier to lose 1 or 2 electrons rather than gain 7 or 6. Thus they tend to become positive ions. For non-metals (which have 5,6,or 7 electrons in their valence shell) it is much easier to gain 1,2,or 3 electrons and so become negatively charged. For carbon which is right in the middle with 4 electrons it tends to share its electrons with other atoms rather than accept or give off any. This is due to the size of carbon as well as geometric and electromagnetic proerties which you don't need to go into.

    As far as the solubility rules all the alkalines are soluble. As far as the rest,, these typically just need to be memorized, no tricks or short cuts :frown:
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