Use the periodic table to write symbols for the following species: 19 protons, 20 neutrons, 19 electrons

when looking at an atom on the periodic table, we see that within the box are two numbers: one at the top and one at the bottom. the top number represents the atomic number and the bottom number represents the mass number. it is always like this for all atoms in the periodic table. The question states that it wants you to to find the atom with 19 protons. before we can even attempt to answer this question, we have to know a few ground rules which apply every time:---Atomic number = proton number - so for example, if an atom has the atomic number of 19, then its proton number is 19 too---Mass number - the atomic number (also proton) = the number of neutrons so for example if the mass number of helium is 4 and its atomic number is 2, therefore the number of neutrons it has is 4-2=2--- The number of protons is equal to the number of electronstherefore to conclude atomic number = proton number = electron numberBUT the above rules only apply for atoms with a neutral chargetherefore using the above rules, we can conduct that the atom we are looking for is potassium