3.1.3.3 Metallic Bonding Flashcards
What is a metallic bond?
Bonds formed between two metals
-strong electrostatic forces of attraction between positively charged metal ions and delocalised electrons
Describe the structure of a metal
A fixed array of positively charged metal ions surrounded by a sea of delocalised electrons, in a lattice structure. The strong electrostatic forces of attraction between the positive ions and delocalised electrons holds the structure together.
Where do the delocalised electrons come from?
Each metal atom loses all of its outer electrons to form positive metal ions, and a sea of delocalised electrons
What forces hold metal structures together?
Strong electrostatic forces of attraction between positive metal ions and delocalised electrons
What affects the strength of the electrostatic forces of attraction in a metal?
-the greater the charge on the positive ion, the stronger the electrostatic forces of attraction as more electrons are delocalised.
-the larger the ion, the weaker the electrostatic forces of attraction. Due to their atomic radius, the nuclear force between the nucleus and delocalised electrons decreases.
What is an alloy?
When other atoms are added to a metal, disrupting the layers and making a stronger material.
Why are metals malleable and ductile?
Layers can slide over each other when a force is applied. As forces act in all directions, the structure does not break when layers move, so the structure can change shape without breaking.
Why are metals strong, and have high melting and boiling points?
There are many strong electrostatic forces of attraction between the positive metal ions and negative electrons, which require lots of energy to overcome.
NOTE: more outer electrons = higher mp/bp and stronger metal
Why are metals good electrical conductors?
There are many delocalised electrons that form a sea of delocalised electrons, which are free to move through the structure and carry electrical charge. (More outer electrons = better electrical conductor)
Why are metals good thermal conductors?
Ions are closely packed so thermal energy can be transferred efficiently through the structure through vibration.
Why are metals good thermal conductors?
Ions are closely packed so thermal energy can be transferred efficiently through the structure through vibration.
