HELP how do i tell whether a polyatomic compound is covalent or ionic?

i know how to tell with 2 elements: covalent is 2 non-metals & ionic is 2 metals. but when they give me 3 element problems im confused.

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  • Dr W
    Lv 7
    2 weeks ago

    you have to memorize common polyatomic ions

    https://o.quizlet.com/RgcayCX4JN.-uGvKsaGL-Q_b.png

    and how they are named

    https://answers.yahoo.com/question/index?qid=20160...

    https://answers.yahoo.com/question/index?qid=20150...

    and all of those are covalently bonded ions.  if they are bonded to H, they are probably not ionic.  If they are bonded to a metal (Na, K, Li, Ca, etc) they are probably ionic compounds.  

    and you need to think about ionic compounds as breaking into say 2 particles, 1 with multiple atoms.. like this

    .. 1 NaClO ---> 1 Na(+) + 1 ClO(-)

    similar to 

    .. 1 NaCl ----> 1 Na(+) + 1 Cl(-)

    see this pic

    https://upload.wikimedia.org/wikipedia/commons/c/c...

    that's how potassium bromide exists in a crystal lattice

    the purple represents K(+) ions.  the brown represents Br(-) ions

    now imagine the purple represents Na(+) and the brown represents the ClO(-) ion.  thats how NaClO exists.  the ClO is like 1 particle

  • 2 weeks ago

    Covalent - Two non metals

    Ionic - Non metal + metal

    Polyatomics -  Are they all 3 non metals? Or do they have 2 non metals and 1 metal? 2 metals and 1 non metal? 

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