The radius of a hydrogen atom is about 0.37 å, and the average radius of the earth’s orbit around the sun is about 1.5 x 108 km. find the ratio of the average radius of the earth’s orbit to the radius of the hydrogen atom

What is lincoln's purpose in writing this speech? question 1 options: to stress the difficulties of war to honor those who died in the war to call for an end to the war to call the country to join a new war

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

Which position represents spring in the southern hemisphere? a) b) c) d)