PROPERTIES OF ALKALI METALS
- Found in Group 1 of the periodictable.
- Solids at room temperature.
- Low melting points compared to other metals.
- Soft metals (can be cut with a knife)
- All alkali metals are held together with metallic bonding.
REACTING WITH WATER
WHEN ALKALI METALS REACT WTH WATER:
-They form a METAL HYDROXIDE and HYDROGEN GAS
-Metal hydroxides are alkaline.
lithium + water >>>>>> lithium hydroxide and hydrogen
2Li(s) + 2H20(l) >>>>>>>> 2LiOH(aq) + H2(g)
REACTIVITY OF ALKALI METALS
THE REACTIVITY OF THE METAL INCREASES AS YOU GO DOWN THE GROUP.
for example: Lithium reacting with water only floats on the water and fizzes, wheras Sodium reacts more vigorously that lithium and ALSO has a lower melting point.
-elements at the BOTTOM of the periodic table have more electrons, so more electron shells as well than the elements at the top of the table.
- this means outer electrons are much further away from the nucleus and the force between the positive and negative charges is much weaker.
- eg. the outer electron in CAESIUM is held much weaker than the outer electron in LITHIUM, and so is more reactive as it is lost easier.