How is milk souring a chemical change?

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

To apply in a gold the individual gold atoms are united to each other by means of a metallic bond. how would you use the gold block to determine the atomic radius of a gold atom?

If 15 drops of ethanol from a medicine dropper weigh 0.60g, how many drops does it takes from a dropper to dispense 1.0ml of ethanol? density of ethanol is ethanol is 0.80g/ml.