Question

Physical and chemical properties of radon , helium,krypton,carbon,

Answer 1

The noble gases are colorless, odorless, tasteless, and nonflammable under standard conditions. They were once labeled group 0 in the periodic table because it was believed they had a valence of zero, meaning their atoms cannot combine with those of other elements to form compounds. However, it was later discovered some do indeed form compounds, causing this label to fall into disuse. The noble gases have full valence electron shells. Valence electrons are the outermost electrons of an atom and are normally the only electrons that participate in chemical bonding. Atoms with full valence electron shells are extremely stable and therefore do not tend to form chemical bonds and have little tendency to gain or lose electrons. However, heavier noble gases such as radon are held less firmly together by electromagnetic force than lighter noble gases such as helium, making it easier to remove outer electrons from heavy noble gases.

As a result of a full shell, the noble gases can be used in conjunction with the electron configuration notation to form the noble gas notation. To do this, the nearest noble gas that precedes the element in question is written first, and then the electron configuration is continued from that point forward. For example, the electron notation of phosphorus is 1s2 2s2 2p6 3s2 3p3, while the noble gas notation is [Ne] 3s2 3p3. This more compact notation makes it easier to identify elements, and is shorter than writing out the full notation of atomic orbitals.

Xenon compounds are the most numerous of the noble gas compounds that have been formed.[33] Most of them have the xenon atom in the oxidation state of +2, +4, +6, or +8 bonded to highly electronegative atoms such as fluorine or oxygen, as in xenon difluoride (XeF

2), xenon tetrafluoride (XeF

4), xenon hexafluoride (XeF

6), xenon tetroxide (XeO

4), and sodium perxenate (Na

4XeO

6). Xenon reacts with fluorine to form numerous xenon fluorides according to the following equations:

Xe + F2 → XeF2

Xe + 2F2 → XeF4

Xe + 3F2 → XeF6

Some of these compounds have found use in chemical synthesis as oxidizing agents; XeF

2, in particular, is commercially available and can be used as a fluorinating agent.

Answer 2

Noble gas, any of the seven chemical elements that make up Group 18 (VIIIa) of the periodic table. The elements are helium (He), neon (Ne),argon (Ar), krypton (Kr), xenon (Xe),radon (Rn), and oganesson (Og). The noble gases are colourless, odourless, tasteless, nonflammable gases. They traditionally have been labeled Group 0 in the periodic table because for decades after their discovery it was believed that they could not bond to other atoms; that is, that their atoms could not combine with those of other elements to form chemical compounds. Their electronic structures and the finding that some of them do indeed form compoundshas led to the more appropriatedesignation, Group 18.