The smallest atom in the periodic table in terms of mass is hydrogen, which has only one proton and one electron. Hydrogen has no neutrons. The element has an atomic number of 1 and atomic weight of 1.00794, making it the smallest of all the elements.Know More
Henry Cavendish first recognized hydrogen as its own element in 1766. It takes its name from the Greek words "hydros" and "genes," which mean "water forming."
Hydrogen is the most abundant element in the universe. It is the main component of the atmospheres of several planets. The sun relies on hydrogen as a source of its energy production. On Earth, hydrogen forms many important compounds, including water (h2O,) hydrochloric acid (HCl) and ammonia (NH3.)Learn more about Atoms & Molecules
The symbol "Cd" stands for the element cadmium on the periodic table. The atomic number of cadmium is 48, and its atomic weight is 112.404 atomic mass units. Cadmium is a heavy metal that belongs to the fifth period on the periodic table.Full Answer >
On the periodic table, the seven horizontal rows are called periods. On the left-hand side of the periodic table, the row numbers are given as one through seven. Moving across a period from left to right, the atomic number of the elements increases.Full Answer >
Mendeleev arranged the periodic table in order of increasing atomic weight of the elements. He determined that there was a pattern when he arranged these elements into horizontal rows.Full Answer >
The heaviest metal on the periodic table of elements is osmium. Its density is 22.57 grams per cubic centimeter, which is twice that of the element lead. A quarter-gallon of osmium weighs 50 pounds when compared to a quarter-gallon of water, which weighs only 2.2 pounds.Full Answer >