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.
Atoms are the smallest bits of ordinary matter and are made from particles called protons (which carry a positive electrical charge), neutrons (which carry no electrical charge) and electrons (which carry a negative electrical charge). An element is a substance that is made entirely from one type of atom. For example, the element hydrogen is made from atoms containing just one proton and one electron. If you had very, very good eyes and could look at the atoms in a sample of hydrogen, you would notice that most of the atoms have no neutrons, some of them have one neutron and a few of them have two neutrons.