Bonding M And c Flashcards
What type of elements contain metabolic bonding
Metals
Structure of metallic bonding
Metallic bombing is the electrostatic attraction between positive ions and the sea of the delocalised electrons
Strength of MB
Strong, they have high melting and boiling points due to large amounts of energy needs to break the strong metallic bonds
Metallic bonding across a period
Across a period the nuclear Increases, causing electrons become more strongly attracted to the nucleus. This means more energy is required to break these attractions hence the higher melting boiling points.
MB down a group
Down the group the number of electron shells increases meaning the outer electrons are further away from the nucleus therefore less strongly attracted this week are attractions require less energy to break hence the low melting and boiling point
Covalent network structure
Contains a giant lattice of nonmetal atoms bonded by strong covalent bonds
Why do these elements have such high melting and boiling points?
Due to their need to break the strong bonds that require a lot of energy to break
The three top dogs in the covalent network structure
•Boron
•silicon
•carbon ( diamond and graphite)
Silicon and diamonds structure
4 atoms bonded by covalent bonds in a gigantic tetrahedral structure
Boron
Each atom is bonded to only 3 atoms rather than 4
Graphite structure
And graphite the carbon atoms form layers of hexagonal rings. These rings are held together by LDF, the forces between the layers are much weaker than covalent bonds which allow layers to slide across each other.
What does that allow
Graphite to be used as lead in pencils
What happens within each layer
The carbon atoms use three out of their four electrons to form covalent bonds and the other electron is free to move about
The electron that moves about is a delocalised iron and it’s also seen where
In metallic bonding and like metallic bonding its presence here allows graphite to conduct electricity
What is a molecule?
A molecule is a group of atoms altogether by covalent bonds
What are covalent molecular substances made of?
They’re made up of molecules with weak London dispersion forces between the molecules
What’s the strength of covalent molecular elements?
Low melting and boiling points because their forces are weak between the molecules and only other forces are broken, not strong covalent bonds
