Bonding Flashcards
Why do atoms react?
To achieve a full highest energy level
What is ionic bonding?
The transfer of electrons from a metal to a non metal
What are ionic bonds?
The strong electrostatic forces of attraction between ions
Why do ionic compounds have high melting and boiling points?
Because it takes a lot of energy to break the many strong ionic bonds which hold a giant ionic lattice together
What is the structure of ionic compounds?
A giant ionic lattice where each positive ion is surrounded by negative ions and each negative ion is surrounded by positive ions in a three dimensional structure
Why do ionic compounds only conduct electricity when melted, molten or dissolved in water?
Because then the ions are free to move and carry charge
What is covalent bonding?
The sharing of electrons between non metals to achieve a full highest energy level
What are the properties of simple molecules?
Low melting and boiling points
They don’t conduct electricity
What is the structure of simple molecules?
The covalent bonds within the molecules are strong but the forces between the simple molecules are weak intermolecular forces that don’t require a lot of energy to overcome
Why don’t simple molecules conduct electricity?
They have no overall charge and there are no free ions or electrons to carry electrical charge
What is an allotrope?
A different physical form of the same element; diamond and graphite are examples of allotropes - they both have different physical properties but are both made of carbon atoms only
What are the properties of diamond?
Giant covalent
Very hard
High melting and boiling point
Very unreactive
Insoluble in water
What is the structure of diamond?
In diamond, each carbon atom is joined to four other carbon atoms by strong covalent bonds; it takes a lot of energy to break down the lattice so it has a very high melting point
What are the properties of graphite?
High melting point
Can conduct electricity
Can be used as a lubricant as its slippery
What is the structure of graphite?
In graphite, carbon atoms are arranged in layers called graphene. Each carbon atom is covalently bonded to three other carbon atoms, arranged in hexagons and there are no covalent bonds between the layers - only weak intermolecular forces - meaning that they slide over each other
Why can graphite conduct electricity?
Because it has delocalised electrons that are free to carry charge
What are some properties of graphene?
It’s incredibly thin and is useful in electronics
It’s stronger than graphite and is also a better conductor of heat and electricity
What is a fullerene?
A simple molecular structure made up of carbon atoms with hollow shapes, usually made up of hexagonal rings with 6 carbon atoms
What are some properties of fullerenes?
The buckminsterfullerene molecule has 60 carbon atoms
Fullerenes can conduct electricity because they have delocalised electrons
Can be used in medicine, as catalysts, lubricants, strengthening materials and in electronics
What is a carbon nanotube and what can it be used for?
A fullerene arranged in a long, hollow cylindrical structure
They have a much lower density than electrical wiring which makes them lighter for the same size of wire which could be useful on aircrafts. Can also be used to reinforce tennis rackets and other materials to make them strong and light
What is metallic bonding?
The electrostatic force of attraction between the delocalised electrons and the positively charged metal ions
Why are alloys created?
Pure metals only contain one type of atom that are all the same size and arranged in layers; this means that the layers can easily slide over each other and the metal is soft. They are too soft for some uses and need to be mixed with other metals to make them harder - an alloy
Why is an alloy stronger than a pure metal?
There are different sizes of atoms in an alloy and the layers are distorted which makes it more difficult for the layers to slide over each other
What is nanoscience?
It refers to structures that are 1-100 nm in size and nanoparticles only contain a few hundred atoms
What are coarse and fine particles?
Coarse particles contain many thousands of atoms and fine particles contain thousands of atoms
What are the charges of:
Hydroxide
Nitrate
Carbonate
Ammonium
Phosphate
OH-
NO3-
CO4²-
NH4+
PO4³-
