Total weight = 1 + 35.45 + 3 * 16 = 84.45
H = 1 / 84.45 * 100% = 1.18%
Cl = 35.45 / 84.45 * 100% = 41.98%
O = 48 / 84.45 * 100% = 56.84%
Answer:
D. Protons ; neutrons.
Explanation:
For a given element the number of protons is fixed, but the number of neutrons differ because the element usually consist of a number of isotopes.
For example Carbon has isotopes which contain 12, 13 and 14 neutrons.
So that is why you average the number of neutrons to find the approximate atomic mass..
A gamma ray has a mass and atomic number of 0 meaning it doesn’t effect the nucleus.
E.g
60 60 0
Co —> Co + gamma ray
27 27 0
Rare earth elements are a series of chemical elements found in the earth's crust and are vital to many of the modern technologies in the world such as computers and networks, advanced transportation and consumer electronics. They help fuel economic growth, maintain high living standards and even save lives. Examples include:
Scandium. Used in television and fluorescent lamps.
Yttrium. Used in cancer treatment drugs, superconductors and camera lenses
Lanthanum. Used to make special optical glasses, telescope lenses and also in petroleum refining.
Neodymium. Used in making some of the strongest permanent magnets, found in most modern vehicles and aircraft.
