Unit 12 Flashcards
Properties of metals
They are strong
They are malleable
They are ductile
They are sonorous (they make a ringing noise when you strike them)
They are shiny when polished
They are good conductors of electricity And heat
They High melting melting and boiling points (they are all solid at room temperature, except mercury)
They have density (they are heavy)
They react with oxygen to form oxides
When they react, metals form positive ions
(The last two properties were chemical properties whilst the rest was physical)
Metals reactivity
A reactive element has a strong drive to become a compound. So it reacts readily with other elements and compounds.
If a metal is more reactive than another metal, then it displaces it and takes it place
The reactivity series
Potassium, k
Sodium , an Can’t reduce their
Calcium , ca Oxides
Magnesium, mg
Aluminium, al
———————————————-
Zinc , zn
Iron , fe Displace hydrogen from acids
Lead, pb And hydrogen can’t reduce
Hydrogen, H. Their oxides
———————————————-
Copper, cu
Silver, ag
Gold, au
Things to remember about the reactivity series
The reactivity series is a list of metals in order of there drive to form positive ions. The more reactive the metal, the more easily it gives up electrons go form positive ions.
A metal will react with a compound of a less reactive metal ( for example an oxide) by pushing the less reactive metal out of the compound and taking its place, as ions.
What happens when a metal is more reactive in the reactivity series
The more reactive the metal the more stable the compounds are
The more reactive the metal, the more difficult it is to extract ores
What happens when the metal is less reactive in the reactivity series
The less it likes to form a compound
The stability of some metal compounds
1.Carbonates
Most decompose to oxide and carbon dioxide on heating
But the carbonates of potassium and sodium do not decompose
Strong heating is needed to break down calcium carbonate and the reaction is reversible
The further down the series, the more easily other carbonates break down
The stability of some metal compounds
2. Hydroxides
Most decompose oxide to oxide and water on heating
But the hydroxide of potassium and sodium do not decompose
The further down the series, the more easily the others break down
What is thermal decomposition
The breakdown of a compound by heating it
The stability of some metal compounds
3. Nitrates
All decompose on heating- but not all the same products
Potassium and sodium nitrates break down to nitrites, releasing only oxygen
But the nitrates of the other metals break down further to oxides releasing the brown gas nitrogen dioxide as well as oxygen
The further down the series the more easily they break down
Uses of the reactivity series
The thermite process
The sacrificial process of ion
Galvanizing
Making cells (batteries)
