An explosion, because the alkali metal react violently up when they touch water. When added to water the metal becomes a +1 ion, and the water forms OH- and H2 gas. The reaction with water is very exothermic, fast and violent. If a lump of lithium, sodium or potassium is placed in cold water, the metal floats; it may melt and move around the surface of the water with 'fizzing'. If universal indicator is added, it changes from green (pH 7) to purple (pH 13-14), showing an alkaline metal hydroxide was formed. The colourless gas hydrogen is also given off and pops with lit splint - but this is not the best of experiments to collect it from! The more reactive the metal, the more vigorous the reaction. Lithium and sodium do not normally cause a flame but the potassium reaction is exothermic enough to ignite the hydrogen. o 2H2(g) + O2(g) => 2H2O(l) o The hydrogen flame turns lilac due to hot potassium atoms in it. o Note: in flame tests hot lithium atoms give a crimson colour and sodium a yellow colour (more details). Rubidium, caesium and francium are very explosive with water. Down the group the reaction gets faster and more violent as the metal gets more reactive i.e. Li < Na < K < Rb < Cs < Fr. The reaction equation for sodium is in words and symbols... sodium + water ==> sodium hydroxide + hydrogen 2Na(s) + 2H2O(l) ==> 2NaOH(aq) + H2(g) and the equations are similar for any of the other Alkali Metals since they are in the same group of the Periodic Table, they behave chemically in the same way. Theoretically Francium is the most reactive and therefore the most explosive metal when in contact with water. See the Related Questions to the left for more information.
Also watch the linked videos of massive explosions due to sodium mixing with water! BOOM!!!
!!DBR!!
Alkali metals
False!
Alkali metals are soft, low density metals that react vigorously with water to form hydrogen. They only have one electron in it's outer shell. Alkali-earth metals are low density hard metals that react less vigorously with water. They have two electrons in the outer shell.
Alkali Metals are the elements (metals) in group one.
Alkali metals have one valence electron.
Hydrogen and alkali metals have one valence electron.
All alkali metals have one valence electrons.
Alkali metals are famous for their vigorous reactions with water, and these reactions become increasingly violent as one moves down the group. The Reaction of Alklali metals as folow: Alkali metal + water → Alkali metal hydroxide + hydrogen gas
Hydrogen is above the alkali metals because it only has one electron, while the alkali metals all have one electron in their OUTER shells.
Alkali Metals: the alkali metals are found in the first group of the periodic table, Alkali metals are very reactive metals and they are not freely in their nature, alkali metals have one electron in their outermost shell. therefore alkali metals are ready to loose that one electron for bonding with other elements, alkali metals are good conductor of electricity and heat. they are soft in nature than other metals.The Alkali Metals are:lithium, sodium, potassium, rubidium cesium, francium
Alkali metals are used in group one of the periodic table
The Alkali metals melt in water so: Rubidium is one example of a metal that melts in water.