Iron reacts with oxygen in a chemical hand-warmer. how should this reaction be categorized?
as an exothermic process because it releases heat
as an endothermic process because it releases heat
as an exothermic process because it absorbs heat
as an endothermic process because it absorbs heat

1)each group 16 element has how many valence electrons? ( )4 ( )6 ( )8 ( )16 2)how many dots appear in the dot structure for calcium ion, ca2+? ( )zero ( )one ( )two ( )eight 3) which of the following atoms forms a cation to obtain an octet of outer shell electrons? ( )magnesium ( )oxygen ( )fluorine ( )helium 4) an al3+ ion contains 13 protons and 10 electrons. ( )true ( )false 5) valence and non-valence electrons are represented in lewis dot structures. ( )true ( )false