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Reactivity then refers to the rate at which a chemical substance tends to undergo a chemical reaction in time. In pure compounds , reactivity is regulated by the physical properties of the sample. For instance, grinding a sample to a higher specific surface area increases its reactivity.
The atomic number increases within the same period while moving from left to right, which in turn increases the effective nuclear charge. The increase in attractive forces reduces the atomic radius of elements. When we move down the group, the atomic radius increases due to the addition of a new shell. [5] [6] [7]
Their reactivity increases going down the group: while lithium, sodium and potassium merely burn in air, rubidium and caesium are pyrophoric (spontaneously catch fire in air). [ 84 ] The smaller alkali metals tend to polarise the larger anions (the peroxide and superoxide) due to their small size.
The reactivity series is sometimes quoted in the strict reverse order of standard electrode potentials, when it is also known as the "electrochemical series". [ 8 ] The following list includes the metallic elements of the first six periods.
Metallic character increases going down a group and from right to left across a period. Nonmetallic character increases going from the bottom left of the periodic table to the top right. The first periodic table to become generally accepted was that of the Russian chemist Dmitri Mendeleev in 1869; he formulated the periodic law as a dependence ...
With continued increase in temperature, performance decreases rapidly (Q 10 of 0.2-0.8) up to a maximum temperature at which all biological function again ceases. [5] Within vertebrates, different skeletal muscle activity has correspondingly different thermal dependencies.
Iron rusting has a low reaction rate. This process is slow. Wood combustion has a high reaction rate. This process is fast. The reaction rate or rate of reaction is the speed at which a chemical reaction takes place, defined as proportional to the increase in the concentration of a product per unit time and to the decrease in the concentration of a reactant per unit time. [1]
The reactivity of these five classes of compounds covers a broad range; the relative reaction rates of acid chlorides and amides differ by a factor of 10 13. [ 2 ] A major factor in determining the reactivity of acyl derivatives is leaving group ability, which is related to acidity.