Key Terms

acid anhydride

compound that reacts with water to form an acid or acidic solution

alkaline earth metal

any of the metals (beryllium, magnesium, calcium, strontium, barium, and radium) occupying group 2 of the periodic table; they are reactive, divalent metals that form basic oxides

allotropes

two or more forms of the same element, in the same physical state, with different chemical structures

amorphous

solid material such as a glass that does not have a regular repeating component to its three-dimensional structure; a solid but not a crystal

base anhydride

metal oxide that behaves as a base towards acids

bicarbonate anion

salt of the hydrogen carbonate ion, ${\text{HCO}}_3{}^{-}$

bismuth

heaviest member of group 15; a less reactive metal than other representative metals

borate

compound containing boron-oxygen bonds, typically with clusters or chains as a part of the chemical structure

carbonate

salt of the anion ${\text{CO}}_3{}^{2-};$ often formed by the reaction of carbon dioxide with bases

chemical reduction

method of preparing a representative metal using a reducing agent

chlor-alkali process

electrolysis process for the synthesis of chlorine and sodium hydroxide

disproportionation reaction

chemical reaction where a single reactant is simultaneously reduced and oxidized; it is both the reducing agent and the oxidizing agent

Downs cell

electrochemical cell used for the commercial preparation of metallic sodium (and chlorine) from molten sodium chloride

Frasch process

important in the mining of free sulfur from enormous underground deposits

Haber process

main industrial process used to produce ammonia from nitrogen and hydrogen; involves the use of an iron catalyst and elevated temperatures and pressures

halide

compound containing an anion of a group 17 element in the 1− oxidation state (fluoride, F⁻; chloride, Cl⁻; bromide, Br⁻; and iodide, I⁻)

Hall–Héroult cell

electrolysis apparatus used to isolate pure aluminum metal from a solution of alumina in molten cryolite

hydrogen carbonate

salt of carbonic acid, H₂CO₃ (containing the anion ${\text{HCO}}_3{}^{\text{−}})$ in which one hydrogen atom has been replaced; an acid carbonate; also known as bicarbonate ion

hydrogen halide

binary compound formed between hydrogen and the halogens: HF, HCl, HBr, and HI

hydrogen sulfate

${\text{HSO}}_4{}^{-}$ ion

hydrogen sulfite

${\text{HSO}}_3{}^{-}$ ion

hydrogenation

addition of hydrogen (H₂) to reduce a compound

hydroxide

compound of a metal with the hydroxide ion OH⁻ or the group −OH

interhalogen

compound formed from two or more different halogens

metal (representative)

atoms of the metallic elements of groups 1, 2, 12, 13, 14, 15, and 16, which form ionic compounds by losing electrons from their outer s or p orbitals

metalloid

element that has properties that are between those of metals and nonmetals; these elements are typically semiconductors

nitrate

${\text{NO}}_3{}^{-}$ ion; salt of nitric acid

nitrogen fixation

formation of nitrogen compounds from molecular nitrogen

Ostwald process

industrial process used to convert ammonia into nitric acid

oxide

binary compound of oxygen with another element or group, typically containing O²⁻ ions or the group –O– or =O

ozone

allotrope of oxygen; O₃

passivation

metals with a protective nonreactive film of oxide or other compound that creates a barrier for chemical reactions; physical or chemical removal of the passivating film allows the metals to demonstrate their expected chemical reactivity

peroxide

molecule containing two oxygen atoms bonded together or as the anion, ${\text{O}}_2{}^{\mathrm{2-}}$

photosynthesis

process whereby light energy promotes the reaction of water and carbon dioxide to form carbohydrates and oxygen; this allows photosynthetic organisms to store energy

Pidgeon process

chemical reduction process used to produce magnesium through the thermal reaction of magnesium oxide with silicon

polymorph

variation in crystalline structure that results in different physical properties for the resulting compound

representative element

element where the s and p orbitals are filling

representative metal

metal among the representative elements

silicate

compound containing silicon-oxygen bonds, with silicate tetrahedra connected in rings, sheets, or three-dimensional networks, depending on the other elements involved in the formation of the compounds

sulfate

${\text{SO}}_4{}^{\mathrm{2-}}$ ion

sulfite

${\text{SO}}_3{}^{\mathrm{2-}}$ ion

superoxide

oxide containing the anion ${\text{O}}_2{}^{-}$