It is a soft, silvery-white alkali metal. Niobium is a chemical element with atomic number 41 which means there are 41 protons and 41 electrons in the atomic structure. Note that, these points are associated with the standard atmospheric pressure . Thulium is a chemical element with atomic number 69 which means there are 69 protons and 69 electrons in the atomic structure. It is also sometimes considered the first element of the 6th-period transition metals and is traditionally counted among the rare earth elements. The chemical symbol for Hydrogen is H. With a standard atomic weight of circa 1.008, hydrogen is the lightest element on the periodic table. Our Website follows all legal requirements to protect your privacy. Lawrencium is a chemical element with atomic number 103 which means there are 103 protons and 103 electrons in the atomic structure. The chemical symbol for Holmium is Ho. Tin is a chemical element with atomic number 50 which means there are 50 protons and 50 electrons in the atomic structure. Note that, these points are associated with the standard atmospheric pressure. Adding a heat will convert the solid into a liquid with no temperature change. The chemical symbol for Protactinium is Pa. Protactinium is a dense, silvery-gray metal which readily reacts with oxygen, water vapor and inorganic acids. Promethium is a chemical element with atomic number 61 which means there are 61 protons and 61 electrons in the atomic structure. Technetium is the lightest element whose isotopes are all radioactive; none are stable. The chemical symbol for Chromium is Cr. These elements, along with the chemically similar elements scandium and yttrium, are often collectively known as the rare earth elements. Covalent bonds often result in the formation of small collections of better-connected atoms called molecules, which in solids and liquids are bound to other molecules by forces that are often much weaker than the covalent bonds that hold the molecules internally together. The chemical symbol for Lithium is Li. The commercial use of beryllium requires the use of appropriate dust control equipment and industrial controls at all times because of the toxicity of inhaled beryllium-containing dusts that can cause a chronic life-threatening allergic disease in some people called berylliosis. Nobelium is the tenth transuranic element and is the penultimate member of the actinide series. Lutetium is a silvery white metal, which resists corrosion in dry air, but not in moist air.