Some elements on the periodic table are oxygen, helium, arsenic and fluorine. Oxygen is an odorless, tasteless and colorless gas at room temperature, but is bright blue as a liquid. Oxygen is a very reactive element and ... More »

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The periodic table arranges the known elements in order of increasing atomic number, which typically coincides with increasing atomic mass. Different rows on the table are known as periods. The period number assigned to ... More »

Neon is the least reactive element on the periodic table. As a noble gas, neon is colorless and odorless with extremely low reactivity in its natural state. Neon has an atomic number of 10. More »

The 13 elements that are room temperature gases are radon (Rn), xenon (Xe), krypton (Kr), argon (Ar), chlorine (Cl), neon (Ne), fluorine (F), oxygen (O), nitrogen (N), helium (He) and hydrogen (H). Most non-metals in the... More »

Arsenic is not particularly reactive though yellow arsenic is the most reactive and reacts with halogens under controlled conditions, fluorine and slowly with air (oxidization only). Arsenic does not react with water and... More »

The periodic table's name comes from the fact that it arranges the elements into repeating sets, otherwise known as "periods." These periods are defined by the covalence of an element, the number of electrons it has in i... More »

The horizontal rows on the periodic table of the elements are called periods. Every element in a period has the same number of atomic orbitals. For instance, hydrogen and helium are in the first period, so they both have... More »