Alkali metals. Flashcards
Where are the alkali metals?
In group 1 of the periodic table
What do the alkali metals have in common?
They all have one electron in their outer shell
How do you identify the alkali metals using the flame test?
Some of the metals will change the colour of the flame
What is an example of an oxidation reaction?
Alkali metal and oxygen
What would an alkali metal + oxygen make?
Alkali metal oxide
When you go down group one does the reactivity increase or decrease?
It increases.
How do elements in group one react?
it gives away its outer electron
why would the reactivity increase as you go down group one?
the nucleus holds on to the electrons so since there are more electrons in an element as you go down group the outer electron is less tightly held as it is further from the nucleus.
what does alkali metal + water make?
alkali metal hydroxide + hydrogen
when doing the flame test, what colour will the flame be with lithium?
red
when doing the flame test, what colour will the flame be with sodium?
yellow
when doing the flame test, what colour will the flame be with potassium
lilac
what happens when you put lithium in water?
it bubbles and fizzes around
what happens when you put sodium in water?
fizzes, gives off heat and can explode
what happens when you put potassium in water?
it moves around the surface of the water quick and it ignites which also ignites hydrogen gas, then sparks and a lilac flame appear
if ui goes from green to purple during the reaction as a metal hydroxide forms, what would this tell you about the metal hydroxide’s pH?
it is high
How do you know when hydrogen is produced from a reaction making a metal hydroxide?
the hydrogen will cause bubbling during the reaction
do the alkali metals have a high or low melting point?
they have the lowest melting points of any nongaseous group in the periodic table
how can you describe the trend in melting and boiling point in group one?
they both decrease as you go down the group
why are alkali metals stored in oil?
to minimise contact with oxygen or water as it reacts vigorously with these two
why do the alkali metals react in a similar way?
since they all have one outer electron, they all have similar chemical properties
can you name two properties of alkali metals?
good conductors of heat, good conductors of electricity
name a trend the elements in group one have?
they get softer as you go down the group
what are alkali metals used for?
can be used to make batteries, air purification and aluminium production
