Denise Badalich, age l1, of So. St. Paul, Minn., for her question:
How many protons are there in an atom?
An atom may have l0 protons or 20, it may have l or 92, and physicists hope to find atoms with more than l03 protons. These figures may lead you to suppose that there is no definite number of protons in an atom. But nothing in the universe could be further from the truth.
The number of protons in this or that atom is fixed and cannot be changed. 2f an atom l0ses one of its protons it becomes a different atom. If it gains a proton it becomes an atom of something else. We know of l03 different atoms, each with its own quota of protons, and nothing can be more definite than the number of protons in the nucleus of each of these atoms.
The natural atoms of the solids, liquids and gases in our planet range one by one from hydrogen, with one proton, to uranium with 92. One by one, nuclear scientists have found and added more atoms to the list. Every neon atom has l0 protons, no more and no less, and every calcium atom has 20. Though the number changes for each type of atom, the protons do not. Each proton in the universe is alike and is the same weight and size.
A proton is a small particle charged with positive electricity and very heavy for its size. The atom has other particles and also tiny electrons that swarm in widely spaced orbits around the central nucleus. The protons are tightly bound in the nucleus, and the lone proton of the hydrogen atom accounts for 99.9 of the weight of the hydrogen atom. Most of an atom is empty space. A thinbleful of tightly packed protons would weigh millions of tons.
The proton is not the biggest or the heaviest atomic particle, but it is the most important. The nature and behavior of an atom depends upon its number of positive charged protons. This is so important to a scientist that he knows the type of atom from which each element is made by the number of its protons. The atomic number of the element gold is 79 because every one of its atoms has 79 protons. The platinum atom has one less and the mercury atom one more proton than gold. If you guessed the atomic number of platinum to be 78 and the atomic number of mercury 80, you are correct.
We are astounded by atomic energy, the tremendous force released when the number of particles in the atomic nucleus is changed. We axe amazed by the chemical wonders that atoms can and do perform, but their number of protons is as simple as one two three. Each element on the list of l03 has an atomic number. The element before it has one less proton and the element following it has one proton more.