The density of gold is 19.3 g/cm the density of iron pyrite is 5.0 g/cm . if a nugget of iron pyrite and a nugget of gold each have a mass of 50 g, what can you conclude about the volume of each nugget

Neils bohr believed that electrons orbited the nucleus in different energy levels, based on strong support from

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

A50.0g sample of liquid water at 0.0 c ends up as ice at -20.0 c. how much energy is involved in this change?