Why can't polyatomic ions ever stand alone?

Which compound contains both ionic and covalent bonds? a) hbr b)cbr4 c)nabr d) naoh

Which of the following shapes would represent a molecule with two bonded atoms and 3 lone pairs on only one of them , trigonal planar , bent , trigonal pyramidal , linear

What type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? view available hint(s) what type of interaction occurs between the r groups of valine and isoleucine in a tertiary structure? salt bridge disulfide bridge hydrogen bond hydrophobic interaction