Structure and Bonding Flashcards
What general properties do metals have
Conduct electricity
Shiny
Malleable
What general properties do most non-metals have
Don’t conduct heat + electricity (insulators)
Weak (brittle)
Dull colour
What type of elements are involved in Ionic bonding
Metal + non-metal
What type of elements are involved in covalent bonding
Non-metal + non-metal
What type of elements are involved in metallic bonding
Metal + Metal
Covalent bonds =……….
Strong
Describe simple molecular bonds
Non metal + non metal
Strong covalent bonds within molecules
Weak intermolecular forces that requires little energy to break
What is a covalent bond
The electrostatic attraction between the positive nuclei and the shared pair of electrons
Are covalent binds weak or strong
They’re strong because of the strong electrostatic attraction
Do simple molecular structures conduct electricity
No - they don’t have a sea of delocalised electrons
It’s an insulator
Why does the melting points of a substance with simple molecular bonds increase
As the molecules get bigger, there are more intermolecular forces, so more energy required to overcome them
Describe giant covalent structures
Strong covalent bonds
Do giant covalent structures conduct electricity
No, they don’t have a sea of delocalised electrons, except GRAPHITE!
Why does diamond have a high melting point
Because of it’s giant covalent structure
With many strong covalent bonds
Which require a lot of energy to overcome
Describe a Giant Ionic structure
Strong ionic bonds
Positive cations
Negative anions
Giant 3D lattice
How and why do ions form
Metal atoms loose electrons to become positive ions with full outer shells
Non-metal atoms gain electrons to become negative ions with full outer shells
Describe the structure of ionic materials
Giant 3D lattice
Why do solid ionic substances not conduct electricity
No delocalised electrons and the ions can’t move
When do ionic substances conduct electricity
When in a liquid state - ions can move
Why do ionic compounds have high melting points
Strong electrostatic forces between oppositely charged ions that require a lot of energy to break
Why does MgO have a higher melting point than NaCl
Magnesium oxide is 2+ 1- and NaCl is 1+ 1-. So MgO has a higher attraction so more energy is needed to overcome this
Describe giant metallic structures
Strong electrostatic attraction between ions
Sea of delocalised electrons
Layers of atoms which can slide over each other
Malleable
Ductile
Describe the structure of metals
Layers of positive cations surrounded by a sea of delocalised electrons
What is metallic bonding
The strong electrostatic attraction between positive metal ions and a sea of delocalised electrons
Why do metallic structures have high melting points
Lots of strong metallic bonds that require a lot of energy to overcome
Why are alloys not as malleable as pure metals
It districts the layers, they can no longer slide over each other
What is diamond used for
Drilling
Whats an allotrope
Atoms of the same element arranged in different ways
Due to the sliding layers, what can graphite be used for
A lubricant
In graphite, there are delocalised electrons between the layers, what does this do
Conducts electricity
Not a metal
