Metallic bonding Flashcards
What are the properties of metals?
Malleable, ductile, good conductors of electricity, shiny
What is the structure of metals?
A lattice made up of positive ions (cations) surrounded by a sea of delocalised electrons
Why can metals conduct electricity?
The delocalised electrons carry charge and can move around freely
What is the overall charge of a metal?
Zero as the positive metal ions cancel out the negative charge of the electrons (how many delocalised electrons per ion)
What is metallic bonding?
Strong electrostatic attraction between cations and delocalised electrons. The stronger the attraction, the stronger the metallic bonding
Why are metals malleable and ductile?
Layers of cations in a lattice can slide over each other, without breaking the metallic bonding
How are metal cations arranged in a solid state?
Lattice
What is the structure of metals in a liquid state (melted)?
Cations are able to flow over each other. Not malleable or ductile, but still shiny and conducts electricity. Slightly weaker metallic bonding
What is the structure of metals in a gaseous state (boiling)?
Separates the structure into individual atoms. Not malleable, ductile, shiny, and doesn’t conduct electricity as all delocalised electrons are now localised to a specific metal atom.
There is no metallic bonding
What gives a metal a high melting and boiling point?
The stronger the metallic bonding, the more energy needed to melt/boil it
Why do metals have high melting and boiling points?
There is a strong attraction between cations and delocalised electrons
Why does melting point increase across a period?
Across a period the ions in a lattice become more highly charged, and the number of delocalised electrons per ion increases. This means there is more electrostatic attraction between cations and delocalised electrons (metallic bonding becomes stronger)
Why does melting point decrease down a group?
Down a group, the atomic radius of the cation increases. This means there is a larger distance between the cations nucleus and the delocalised electrons. The larger the distance, the weaker the attraction.
What are pure metals?
Metals made from one element
What are alloys?
Metals made from two or more elements
