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.

2 Answers

  • Dr W
    Lv 7
    9 months ago

    you have to memorize common polyatomic ions

    and how they are named

    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

    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

  • 9 months 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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