Metals Flashcards
Physical properties of most metals
High density, melting and boiling point
Exceptions to density
Group one metals are less dense than water
Exception to high melting and boiling point
Mercury is a liquid at room temperature and pressure
Appearance and durability of metals
Metals are good conductors of heat and electricity
They are also shiny, malleable and ductile
Why are pure metals not widely used?
They are soft and may corrode easily
What is an alloy?
A mixture of one or more elements, which may or may not be metal
Why are pure metals soft?
It is due to the regular arrangement of their atoms in neat layers which slide past each other easily when a force is applied
Why are alloys harder than pure metal?
In an alloy, the arrangement of atoms is disrupted by the presence of atoms of different sizes
This prevents the layers of atoms form sliding past each other easily, making the alloy harder than a pure metal
Displacement reactions of metals
Displacement reaction takes place when a more reactive metal is placed in the salt solution of a less reactive metal
The more reactive metal has a higher tendency to form ions, hence it displaces the less reactive metal from its salt
What if less reactive metal is placed in a salt solution of more reactive metal?
Then no observable change will be seen
Which metals react with cold water?
Violently: Potassium. Hydrogen gas catches fire and explodes
Violently: Sodium. Hydrogen gas may catch fire
Moderately: Calcium
Slowly: Magnesium
Which metals react with steam?
Violently: hot Magnesium reacts violently with steam and burns with a white glow
Aluminium reacts readily with steam but reaction slows down due to formation of a protective oxide layer
Hot zinc reacts readily with steam. Zinc oxide is yellow when hot and white when cold
Hot iron react slowly with steam
Metals which react violently with dilute hydrochloric acid
Potassium
Sodium
Calcium
Metals which react readily with dilute hydrochloric acid
Magnesium
Aluminium
Zinc (moderately fast)
Metals which react slowly with dilute hydrochloric acid
Iron
