The radius of which of the following orbit is same as that of the first bohr's orbit of hydrogen atom?
a) he+ (n=2)
b) li2+ (n=2)
c) li2+ (n=3)
d) be3+ (n=2)
where n=orbit

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 of the following has wavelength longer than the wavelength of viable light? a) x rays b) gamma rays c) radios waves d) ultraviolet waves

Analyze the reaction to determine whether the reaction is exothermic or endothermic. explain your reasoning.