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.
Radioactive isotopes, also called radioisotopes, are atoms with a different number of neutrons than is usual, making them unstable.A radioisotope's nucleus decays, emitting alpha, beta and gamma rays until the isotope reaches stability.Once itâs stable, the isotope may become another element entirely, such as when uranium decays into lead.ignificance. Radioactive isotopes are useful because they produce alpha, beta and gamma rays. The radiationâs penetrating power depends on its energy, particle mass, and the objectâs density. These properties lead to many practical applications in science, medicine and industry.