To achieve one of these orders of stability, an atom reacts with another atom to stabilize both. Generally, electrons exist in orbitals that are the result of solving the Schrödinger equation for specific situations.Īll things (values of the n and m l quantum numbers) being equal, the order of stability of electrons in a system from least to greatest is unpaired with no other electrons in similar orbitals, unpaired with all degenerate orbitals half filled and the most stable is a filled set of orbitals. Quantum chemistry provides the most in-depth and exact understanding of the reason this occurs.
#Reactivity chart chemistry free
Thermodynamically, a chemical reaction occurs because the products (taken as a group) are at a lower free energy than the reactants the lower energy state is referred to as the 'more stable state'. The second meaning of 'reactivity', that of whether or not a substance reacts, can be rationalised at the atomic and molecular level using older and simpler valence bond theory and also atomic and molecular orbital theory. The half-life of such a species is another manifestation of its stability, but its reactivity can only be ascertained via its reactions with other species. For example, an isolated molecule of an electronically excited state of the oxygen molecule spontaneously emits light after a statistically defined period. 'Stability' should not be confused with reactivity.
For example, in making the statement that 'sodium metal is reactive', we are alluding to the fact that sodium reacts with many common reagents (including pure oxygen, chlorine, hydrochloric acid, water) and/or that it reacts rapidly with such materials at either room temperature or using a Bunsen flame. However, in all cases, reactivity is primarily due to the sub-atomic properties of the compound.Īlthough it is commonplace to make statements that substance 'X is reactive', all substances react with some reagents and not others. In crystalline compounds, the crystalline form can also affect reactivity. In impure compounds, the reactivity is also affected by the inclusion of contaminants. For instance, grinding a sample to a higher specific surface area increases its reactivity. In pure compounds, reactivity is regulated by the physical properties of the sample. Reactivity then refers to the rate at which a chemical substance tends to undergo a chemical reaction in time. Restriction of the term to refer to reaction rates leads to a more consistent view. Hydrogen does not react with oxygen-even though the equilibrium constant is very large-unless a flame initiates the radical reaction, which leads to an explosion.
In fact, the rate of reaction of alkali metals (as evidenced by their reaction with water for example) is a function not only of position within the group but particle size. For example, it is commonly asserted that the reactivity of group one metals (Na, K, etc.) increases down the group in the periodic table, or that hydrogen's reactivity is evidenced by its reaction with oxygen. Both factors are actually distinct, and both commonly depend on temperature. It appears to embody both thermodynamic factors and kinetic factors-i.e., whether or not a substance reacts, and how fast it reacts. Reactivity is a somewhat vague concept in chemistry. The term reactivity is related to the concepts of chemical stability and chemical compatibility.
Equilibrium point of the reaction (i.e., the extent to which all of it reacts).Variety of substances with which it reacts.The chemical reactivity of a substance can refer to the variety of circumstances (conditions that include temperature, pressure, presence of catalysts) in which it reacts, in combination with the: Interacts with two or more other reactants to form two or more products.Forms new substances by addition of atoms from another reactant or reactants.
The chemical reactivity of a single substance (reactant) covers its behavior in which it: theories to predict and to account for these processes.experimental methods that are used to observe these processes.methodology that applies to the study of reactivity of chemicals of all kinds,.the systematic study of sets of reactions of these two kinds,.the chemical reactions of two or more substances that interact with each other,.the chemical reactions of a single substance,.In chemistry, reactivity is the impulse for which a chemical substance undergoes a chemical reaction, either by itself or with other materials, with an overall release of energy. JSTOR ( June 2016) ( Learn how and when to remove this template message).Unsourced material may be challenged and removed.įind sources: "Reactivity" chemistry – news Please help improve this article by adding citations to reliable sources. This article needs additional citations for verification.
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