S-block Flashcards
G1 nitrates
More stable than G2 nitrates
Melt then thermally decompose to form nitrite (NO2-) and O2 (relights a glowing splint)
Eg 2NaNO3 -> 2NaNO2 + O2
Group 1
Alkali metals (form alkaline hydroxides with water)
s1 e- configuration
+1 oxidation state
Low ΔΗ IE
G1 with O2
More reactive down group
Li- red flame
Na- yellow orange flame
K- lilac flame or melts to potassium peroxide
G2
Alkali earth matals (oxides and hydroxides are alkaline)
s2 e- configuration
+2 oxidation state
Low ΔH IE
G2 nitrates
Less stable than G1 nitrates Thermally decomposes to give NO2 (brown gas) O2 (relights glowing splint) the oxide and steam Eg 2Ca(NO2)2hydrate -> 2CaO + 4NO2 + O2 + 6H2O
G2 flame test
Ca- orange red
Sr- crimson
Ba- apple green
G2 with water
Be doesn’t react
Mg burns with steam-> MgO (white solid) + H2 (few bubbles in cold)
Generally cold water -> hydroxide
Steam-> oxide (hydroxides thermally decompose)
G2 with O2
Burns to form simple XO
G2 with acid
XCl2 + H2
G2 carbonates
Undergo thermal decomposition to form metal oxide + CO2
More stable down group