How do coastal sand dunes form in Florida?

They are formed by windblown sand collecting around an obstruction. As organic matter is deposited by wind and waves, low herbs colonize the dune. As these plants collect more sand and organic matter, the dune increases in height becoming the fore dune.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.