CHEMISTRY GLOSSARY

reactive metal    →   reaktivni metal

Reactive metals are metals that readily combine with oxygen at elevated temperatures to form very stable oxides, for example titanium, zirconium, and beryllium. Reactive metals may also become embrittled by the interstitial absorption of oxygen, hydrogen, and nitrogen.

reactivity series    →   reaktivni niz

Reactivity series or activity series is a series of elements (usually metals) ranked by their reactivity degree, made for comparison of reactions of elements with other substances, e.g. acids and oxygen.

reactivity    →   reaktivnost

Reactivity is the tendency of a compound to chemically react with other substances or itself, resulting in the release of energy.

alkali metal    →   alkalijski metal

Alkali metal is a term that refers to six elements: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). These elements make up group 1 of the periodic table of elements. They all form singly charged positive ions, and are extremely reactive. They react violently with water, forming hydroxides and releasing hydrogen gas and heat. Caesium and francium are the most reactive and lithium is the least.

alkaline earth metal    →   zemnoalkalijski metal

Alkali earth metal is a term that refers to six elements: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). These elements make up group 2 of the periodic table of elements. They all exhibit a single oxidation state, +2. They are all light and very reactive. Barium and radium are the most reactive and beryllium is the least.

To denote slightly soluble metal oxides chemists formerly used the term "earth". The oxides of barium, strontium, and calcium resemble alumina (Al₂O₃), a typical "earth", but form alkaline mixtures with water. For this reason barium, strontium, and calcium were called alkaline earth metals. This name has now been extended to include all of the elements of group 2.

alkanes    →   alkani

Alkanes (paraffins) are acyclic branched or unbranched hydrocarbons having the general formula C_nH_2n+2, and therefore consisting entirely of hydrogen atoms and saturated carbon atoms. In the systematic chemical nomenclature alkane names end in the suffix -ane. They form a homologous series (the alkane series) methane (CH₄), ethane (C₂H₆), propane (C₃H₈), butane (C₄H₁₀), etc. The lower members of the series are gases; the high-molecular mass alkanes are waxy solid. Generaly the alkanes are fairly unreactive. They form haloalkanes with halogens when irradiated with ultraviolet radiation. Alkanes are present in natural gas and petroleum.

alkenes    →   alkeni

Alkenes are acyclic branched or unbranched hydrocarbons having one or more double carbon-carbon bonds in their molecules. In the systematic chemical nomenclature, alkene names end in the suffix -ene. The general formula is C_nH_(2n+2)-2x were x is the number of double bonds. Alkenes that have only one double bond form a homologous series: ethene (ethylene), CH₂=CH₂, propene, CH₃CH₂=CH₂, etc. Alkenes typically undergo addition reactions to the double bond.

cycloalkanes    →   cikloalkani

Cycloalkanes are cyclic saturated hydrocarbons containing a ring of carbon atoms joined by single bonds. They have the general formula C_nH_2n, for example cyclohexane, C₆H₁₂. In general, they behave like the alkanes but are rather less reactive.

diazo compounds    →   diazo-spojevi

Diazo compounds are compounds having the divalent diazo group, =N⁺=N^-, attached to a carbon atom. The term includes azo compounds, diazonium compounds, and also such compounds as diazomethane, CH₂=N₂.

radical    →   radikal

Radical is a reaction intermediate where a bond is broken and the two parts of the molecule exist carrying a single unshared electron. The radicals are normally destroyed quickly by recombination or they break into another radical and a stable molecule.