Metallic bonding Flashcards
What is metallic bonding ?
1) Metals consist of giant structure
2) electrons in outer shell of metal atoms are delocalised . There are strong forces of electrostatic attraction between positive metal ions and the shared negative electrons
3) These forces of attraction hold the atoms together in a regular structure which is known as metallic bonding and is very strong
Which substances are held together by metallic bonding and what produces all the properties of the metal ?
- alloys and metallic elements
- delocalised electrons in metallic bond
Why are most metals solid at room temperature
Electrostatic force of attraction between metal atoms and negative sea of delocalised electrons are very strong, so needs a lot of energy to be broken = most compound with metallic bond ( Sodium chloride , Calcium chloride ) have high mp, bp so generally solids at room temperature.
Properties of metals
- delocalised electrons carry electrical charge and Thermal energy through the whole structure so metals are good conductors of electricity and heat
- The layers of atoms in a metal can slide over each other, making metals malleable so can be hammered/bent or rolled into flat sheets
Why are alloys harder than pure metals ?
pure metals - soft so mixed with other metals to make them harder. Most everyday metals are alloys - mixture of two or more elements or a metal and another element. Alloys are more useful (harder) .
Different elements have different sized atoms so when diff elements mixed, it disrupts regular structure and distort layer making it harder to slide over each other.
