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Nonmetals tend to gain electrons during chemical reactions, in contrast to metals which tend to donate electrons. This behavior is related to the stability of electron configurations in the noble gases, which have complete outer shells as summarized by the duet and octet rules of thumb, more correctly explained in terms of valence bond theory. [67]
Electron affinity can be defined in two equivalent ways. First, as the energy that is released by adding an electron to an isolated gaseous atom. The second (reverse) definition is that electron affinity is the energy required to remove an electron from a singly charged gaseous negative ion.
Hydrogen gas is a reducing agent when it reacts with non-metals and an oxidizing agent when it reacts with metals. 2 Li (s) + H 2(g) → 2 LiH (s) [ a ] Hydrogen (whose reduction potential is 0.0) acts as an oxidizing agent because it accepts an electron donation from the reducing agent lithium (whose reduction potential is -3.04), which causes ...
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 most reactive metals, such as sodium, will react with cold water to produce hydrogen and the metal hydroxide: 2 Na (s) + 2 H 2 O (l) →2 NaOH (aq) + H 2 (g) Metals in the middle of the reactivity series, such as iron , will react with acids such as sulfuric acid (but not water at normal temperatures) to give hydrogen and a metal salt ...
It is the softest of the commonly recognised metalloids. Tellurium reacts with boiling water, or when freshly precipitated even at 50 °C, to give the dioxide and hydrogen: Te + 2 H 2 O → TeO 2 + 2 H 2. It has a melting point of 450 °C and a boiling point of 988 °C. Tellurium has a polyatomic (CN 2) hexagonal crystalline structure.
Opposite to covalent bonding, this chemical bond creates two oppositely charged ions. The metals in ionic bonding usually lose their valence electrons, becoming a positively charged cation. The nonmetal will gain the electrons from the metal, making the nonmetal a negatively charged anion. As outlined, ionic bonds occur between an electron ...
In a sodium-vapor lamp for example, sodium atoms are excited to the 3p level by an electrical discharge, and return to the ground state by emitting yellow light of wavelength 589 nm. Usually, the excitation of valence electrons (such as 3s for sodium) involves energies corresponding to photons of visible or ultraviolet light.