Properties of the alkali metals
Following a raid on Alc Alley, the alkali metals (along with their electric robots*), were deemed dangerous and criminal, and were put on the wanted list. The police issued the following statement, warning the public about alkali metals and their devious robots (electrons) and informing them of their properties.
*Each alkali metal has a robot as their sidekick (they have a single electron in their outer shell). It is these robots (electrons) that cause the metals to behave how they do. The robots (electrons) are a bad influence and are responsible for the alkali metals’ unlawful reputation.
Note: Alkali Metals (Group 1 in the periodic table) are entirely different from alkalis (which may be more easily remembered as alkali solutions).
1. Alkali metals like to steal oxygen and form oxides
The police began by explaining that alkali metals had a long criminal history centred on the theft of oxygen.
Potassium + Oxygen → Potassium oxide
4K + O2 → 2K2O
Sodium + Oxygen → Sodium oxide
4Na + O2 → 2Na2O
Lithium + Oxygen → Lithium oxide
4Li + O2 → 2Li2O
2. Alkali metals react violently towards water
The public were warned not to approach an alkali metal and their robot, particularly in the presence of water, as they could be very violent and explosive.
3. Alkali metals are less dense than water so float on its surface
The police said that, like many criminals, the alkali metals believed they were better than others as they were smarter and less dense than water.
4. Alkali metals are soft and easily cut with a knife
Not wanting to inflate the alkali metal’s ego too much, the police went on to say they were soft and easily cut with a knife much like butter.
5. Alkali metals react with water to form solutions called hydroxides
After reading the police statement, the alkali metals and their robots were worried, so their solution was to go and hide in a rock side (hydroxide)
Potassium + water → potassium hydroxide + hydrogen
2K + 2H2O → 2KOH + H2
Sodium + water → sodium hydroxide + hydrogen
2Na + 2H2O → 2NaOH + H2
Lithium + water → lithium hydroxide + hydrogen
2Li + 2H2O → 2LiOH + H2
6. Alkali metals have low melting points
However, this plan didn’t work as the alkali metals and their robot sidekicks soon began to melt under the heat from the police search.
To summarise, alkali metals:
- Have one electron in their outer shell
- Take oxygen atoms from other molecules to form oxides
- React violently with water
- Are less dense than water so they float
- Are soft so can easily be cut with a knife
- Form hydroxides when in a water solution
- Have low melting points compared with other metals