Group 1

alkali metals low m.p. soft metals reactive to air and moisture - stored under oil

Lithium and Sodium produced by electrolysis of their molten Cl- salts 2Na+ + 2e- -> 2Na 2Cl- -> Cl2 + 2e-

all alkali metals burn in air main product of combustion depends on metal 4Li + O2 -> 2Li2O - oxide 2Na + O2 -> Na2O2 - peroxide K + O2 -> KO2 - superoxide (Rb and Cs react similar) combustion in limited amount of O2 leads to intensely coloured suboxides (Rb9O2) dissolution in H2O - hydroxides (MOH) and H2O2 (Na2O2) or O2 (KO2) alkali metals also formed by metals in water - 2M + 2H2O -> 2MOH + H2 - violent except for Li

[in industry] electrolysis of NaCl solution 2NaCl + 2H2O -> 2NaOH + H2 + Cl2 anode and cathode separated by membranes or mercury metal

can be prepared from hydroxides or carbonates with hydrohalic acid Li2CO3 + 2HBr -> 2LiBr + H2O + CO2 form ionic crystal lattices - e.g. NaCl

common binary compounds of alkali metals and carbon (carbides) based on dianion of acetylene (HC≡CH) 2Li + HC≡CH -> Li2C2 + 2H2 Li = 1 of 2 elements (Mg = other) that burns in N2 6Li + N≡N -> 2Li3N compounds with small Li+ = stable (high lattice energy) other salts containing oxoanions (CO3- // NO3-) are also common

alkali metals are only singly charged and relatively large binding of ligands = weaker compared to other cations

strong binding selective for metal ion (size) -too large = not fit -too small = not all oxygens will bind

greatly stabilise M+ and allow synthesis of alkalides (M-) -crypt + 2Na -> [(crypt)Na]+Na- -not thermodynamically stable

gives solvated M+ and free e- - Na -> Na+ + e- solvated e- = dark blue solution (strong reducing agent) e- slowly reduces ammonia -> amides (NH2- ) + H2 H2O can’t react like this (too acidic + explosive)