Mammoth Memory

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.

All alkali metals have one electron in there outer shell which makes them very reactive

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.

Alkali metals like to steal oxygen and from oxides

For example:

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.

Alkali metals react violently to water    

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.

Alkali metals are less dense than water so floats on its surface

 

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.

Alkali metals are soft and can be easily cut with a knife

 

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)

Hydroxide solution is produced when alkali metals react with water

 

For example:

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.

Alkali metals have low melting points

 

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
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