True or false : Formula masses (or molecular masses) and molar masses are calculated to two significant figures.

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

How have the greenhouse gasses increased from the year 2000 to 2018

Avolleyball player hit a ball with a mass of 0.25 kg. the average acceleration of the ball is 15.5 m/s². how much force did the volleyball player apply to the ball? 62.0 n 3.87 n 62.0 m/s² 3.87 m/s²