A C and D are all correct, Helium and Hydrogen only have a 1s orbital, and helium has 2 protons, while hydrogen has 1, and finally Hydrogen has no neutrons while helium has 2. Helium does not however have 8 valence electrons as the 1s orbital can only hold 2, meaning B is the “correct” (false) answer.
Answer: The freezing point depression is 
Explanation:
Depression in freezing point is given by:
= Depression in freezing point
= freezing point constant =
m= molality =
Thus freezing point depression is 
Answer:
=3 means is 3 or greater so that would be f and g subshells
=0 means is 0 or greater so that would be s, p, d, f and g subshells
=1 means is 1 or greater so that would be p, d, f, and g subshells
=4 means is 4 or greater so that would be g only
Answer:
not sure if this is the right way to answer this question but PbS is Phosphate-buffered saline (i think)
Explanation: