Question

An active alkaline metal with 56 protons

Answer 1

In this question, telling you it's an alkaline metal is not needed. 56 protons is sufficient to find which element it is, since atomic number is equal to the number of protons. So, we just find number 56 on the periodic table, Barium.

So, even though I said it was unneeded, I will tell you what "active alkaline metal" tells you. The alkaline metals are the second column of elements on the period table. This would be the column starting with Beryllium. The active alkaline metals start after Magnesium, which would be calcium and below.