Please help me this is very hard and it’s a quiz

What is the percentage by mass of silicon (si) in iron aluminum silicate (fe3al2(sio4)3)?

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

Light travels through space at 186,282 miles per second and it takes about 1.3 seconds for light to travel from the moon to earth. which of the following is the correct method of finding the distance, in miles, between the moon and earth? add 186,282 and 1.3 divide 186,282 by 1.3 multiply 186,282 by 1.3 subtract 1.3 from 186,282