HELP! Type the correct answer in each box. Platinum (Pt) is in the 78th position in the periodic table.
A neutral atom of the element that comes just before platinum in the periodic table has electrons and protons.

Construct the hypothetical phase diagram for metals a and b between room temperature (20c) and 700c, given the following information: * the melting temperature of metal a is 480c. • the maximum solubility of b in a is 4 wt% b, which occurs at 420c. • the solubility of b in a at room temperature is 0 wt% b. • one eutectic occurs at 420c and 18 wt% b–82 wt% a. • a second eutectic occurs at 475c and 42 wt% b–58 wt% a. • the intermetallic compound ab exists at a composition of 30 wt% b–70 wt% a, and melts congruently at 525c.• the melting temperature of metal b is 600c. • the maximum solubility of a in b is 13 wt% a, which occurs at 475c. • the solubility of a in b at room temperature is 3 wt% a.

Can someone me with questions 15 to 17 plz.

If 1.8 l of water is added to 2.5l of a 7.0 m koh solution, what is the molarity of the new solution