The reason you do not know how the “2” got into the chemical formula for the salt is that you have forgotten what you learned in Module 5 (pp. 175-180). When H₂SO₄ gives up its two H 1+ ions, the only thing left is SO₄ 2-, the polyatomic sulfate ion. The K is in group 1, so in ionic compounds, it takes on the charge 1+.

To determine the chemical formula of the ionic compound between SO₄ 2- and K 1+, you switch the charges and drop the signs. Thus, you get K₂SO₄.

You might want to review those Module 5 pages, because you must remember those concepts to understand Module 9.