Total 8,232. Note: In addition to its drugstores, Walgreens also operates home care facilities and specialty, institutional and mail service pharmacies. Its Take Care Health Systems subsidiary manages more than 400 convenient care clinics at Walgreens drugstores.
These different versions of hydrogen are called isotopes. All isotopes of a particular element have the same number of protons, but have a different number of neutrons. If you change the number of neutrons an atom has, you make an isotope of that element.Currently, scientists know of 118 different elements.Some, like gold, silver, copper and carbon, have been known for thousands of years.f you change the number of neutrons an atom has, you make an isotope of that element. Currently, scientists know of 118 different elements. Some, like gold, silver, copper and carbon, have been known for thousands of years.
An isotope is a variant on an element that has a different atomic weight from other variants. Except for the commonest form of hydrogen â which has only a proton â every atomic nucleus in normal matter is made of both protons and neutrons.oo many neutrons can also make an isotope unstable. For example, the commonest form of hydrogen has one proton and no neutrons, but there are two other forms, with one and two neutrons, called deuterium and tritium, respectively.