Pls help ill mark as brainliest :) Q7. Pb + O2 PbO2

Is this combustion, single replacement, double replacement, synthesis, or decomposition

What is the force of attraction between the particles in a salt crystal

Can someone me with questions 12 and 13 plz.

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