As we move across the periodic table, from potassium, K, to krypton, Kr, we see the following changes. All BUT ONE is
correct
A) Elements change from solids to gases.
B) Elements change from metals to metalloids to nonmetals.
C) Valence electrons increase beginning with one and ending with eight.
D) The charge of ions changes: negative to the left and positive to the right

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

Describe the forces both attractive and repulsive that occur as two atoms move closer together.

Phosphoric acid is a triprotic acid ( =6.9×10−3 , =6.2×10−8 , and =4.8×10−13 ). to find the ph of a buffer composed of h2po−4(aq) and hpo2−4(aq) , which p value should be used in the henderson–hasselbalch equation? p k a1 = 2.16 p k a2 = 7.21 p k a3 = 12.32 calculate the ph of a buffer solution obtained by dissolving 18.0 18.0 g of kh2po4(s) kh 2 po 4 ( s ) and 33.0 33.0 g of na2hpo4(s) na 2 hpo 4 ( s ) in water and then diluting to 1.00 l.