What is one fact you learned about the gases in our atmosphere that you did not know ?! need done

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

According to le chatelier’s principle, a system in chemical equilibrium responds to stress by shifting the equilibrium in a direction that reduces the stress. normalizes the stress. increases the stress. changes the stress.

Δu of , in kj/kg, as it isto k, (a)as a of , (b) at , (c) at .