Alkali metals Flashcards
What five things typically happen when an alkali metal reacts with water?
Melting, moving around, fizzing, floating, flame
What is the colour of the flame when sodium reacts with water?
An organge or yellow flame
What is the colour of the flame when potassium reacts with water?
Lilac
What are the products of the reaction between an alkali metal and water?
metal hydroxide + hydrogen
How are alkali metals unlike other metals?
They are soft, not very dense and very reactive
What happens to softness as you go down the group?
The metals get softer
What do alkali metals have on their outside?
Dark oxide layer
What is the appearance of alkali metals when cut?
Silver/grey and shiny
What is lithium used for?
In rechargeable batteries for mobile phones, laptops , etc
What is sodium used for?
Sodium chloride added to food.
As a heat exchanger in some nuclear reactors
What are uses of Potassium
In fertilisers e.g. Potassium chloride.
Important mineral for the body - regulates fluid levels
What are uses of Rubidium and Caesium?
Making atomic clocks
Why does the reactivity of alkali metals increase as you go down the group?
As you go down the group, the number of shells increases and the outer shell electron is further away from the nucleus. The attractive force between the negative electron and the positive nucleus gets weaker, so this electron is easier to lose during a reaction.
Why are ALL alkali metals reactive?
They only need to lose one electron
What happens to melting points as you go down the group?
They decrease
