Question: how many protons neutrons and electrons are there in a neutral atom of 43 k (potassium- 43 )?
Answer: This tells you that potassium has 19 protons and - since the number of protons is the same as the number of electrons- also 19 electrons. To find out the number of neutrons you have to look at the atomic mass or weight of the element. This can also be found in the periodic table.