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The noble gases have also been referred to as inert gases, but this label is deprecated as many noble gas compounds are now known. [6] Rare gases is another term that was used, [ 7 ] but this is also inaccurate because argon forms a fairly considerable part (0.94% by volume, 1.3% by mass) of the Earth's atmosphere due to decay of radioactive ...
The noble gases (helium, neon, argon, krypton, xenon and radon) were previously known as 'inert gases' because of their perceived lack of participation in any chemical reactions. The reason for this is that their outermost electron shells (valence shells) are completely filled, so that they have little tendency to gain or lose electrons.
From left to right in the periodic table, the nonmetals can be divided into the reactive nonmetals and the noble gases. The reactive nonmetals near the metalloids show some incipient metallic character, such as the metallic appearance of graphite, black phosphorus, selenium and iodine. The noble gases are almost completely inert.
The only chemical elements that are stable single atoms (so they are not molecules) at standard temperature and pressure (STP) are the noble gases. These are helium, neon, argon, krypton, xenon, and radon. Noble gases have a full outer valence shell making them rather non-reactive species. [2]
Like the noble gases, the tendency for non-reactivity is due to the valence, the outermost electron shell, being complete in all the inert gases. [4] This is a tendency, not a rule, as all noble gases and other "inert" gases can react to form compounds under some conditions.
Nonmetals show more variability in their properties than do metals. [1] Metalloids are included here since they behave predominately as chemically weak nonmetals.. Physically, they nearly all exist as diatomic or monatomic gases, or polyatomic solids having more substantial (open-packed) forms and relatively small atomic radii, unlike metals, which are nearly all solid and close-packed, and ...
Helium is the smallest and the lightest noble gas and one of the most unreactive elements, so it was commonly considered that helium compounds cannot exist at all, or at least under normal conditions. [1] Helium's first ionization energy of 24.57 eV is the highest of any element. [2]
Plasma: Unlike gases, which are composed of neutral atoms, plasma contains a significant number of free electrons and ionized atoms. It may self-generate magnetic fields and electric currents and responds strongly and collectively to electromagnetic forces. [1]