on the periodic table, there are 2 numbers in the block fir the elenent potassium: k 19 and 39.098 what are the names of the numbers and what do they mesure

It represents as 19 K 39.098

Here, upper number which is 19, is atomic number, which means number of protons or number of electrons in non-ion phase.

And, lower number which is 39.098, is mass number, which means the sum of atomic number & number of neutrons.