C3-structure and Bonding Flashcards
What are the the three states of matter called?
Solids,liquids and gases
What is the position of the particles in each of the three states of matter?
Solid-particle are packed closely together and vibrate around fixed positions
Liquid-the particles are close together but can slip and slide over each other in random motion.
Gas- the particles in a gas have, on average, lots of space between them and zoom around randomly
In melting and boiling how is energy transferred
How is energy transferred in freezing and condensing?
Energy is transferred from the surroundings to the substance
Energy is transferred from the substance to the surroundings
How do elements react together to form compounds
By gaining or loosing or sharing electrons
What is ionic bonding?
Where ionic compounds are held together by strong forces of attraction between their oppositely charged ions.
Why do ionic compounds have high melting and boiling points?
It takes a lot of energy to break the many strong ionic bonds, operating in all directions that hold a giant ionic lattice together. They are also solids at room temperature.
Why can ionic compounds not conducted electricity when they are solids?
Because the ions cannot move. They are locked in place by the strong electrostatic forces of attraction.
Ionic compounds can conduct electricity when they are melted or dissolved in water. Why is this?
The ions can now move and carry the charge due to high temperature provides enough energy to break the bonds-molten and water molecules separate ions from the lattice ions are free to move around within the solution-ionic compound in solution
When are covalent bonds formed?
When atoms of non-metals share pairs of electrons with each other.
Each shared pair of electrons is a covalent bond
Many substances containing covalent bonds consist of simple molecules jug some have giant covalent structures
What do many substances containing covalent bonds consist of?
Simple molecules but some have giant covalent structures
Do substances made up of simple molecules have low melting and boiling points?
Yes
Why do substances made of simple molecules have low melting and boiling points.
The forces between the simple molecules are weak.
Why can simple molecules not conduct electricity?
Because they have no overall charge, so they cannot carry electrical charge.
Why is graphite soft and slippery
Graphite contains giant layers of covalently bonded carbon atoms. However there are no covalent bonds between the layers.this means they can slide over each other, making graphite soft and slippery.
Why can graphite conduct electricity and thermal energy?
Because the delocalised electrons can move along its layers.
What is the general name for all these hollow-shaped molecules of carbon
Fullerenes which can form large cage like structures and tubes based on hexagonal rings of carbon atoms
What are uses for fullerenes?
A transport mechanism for drugs to specific sites of the body
Catalysts
And as a reinforcement for composite materials
Graphene is a single layer of graphite and so is just one atom thick. What are its properties
Excellent electrical conductivity will help create new developments in the electronics industry in the future
How are atoms in metals arranged?
They are closely packed together and arranged in regular layers
What is metallic bonding?
The bond produced due to the combination of electrostatic force of attraction between the negative electrons and the positive nucleus of metal atoms
Why can the metals be bent and shaped?
Because the layers of atoms in a giant metallic structure can slide over each other
Why are alloys harder than pure metals
Because the regular layers in a pure metal are distorted by atoms of different sizes in an alloy
What is nano-science
The study of small particles between 1 and 100 nanomètres in size
Nanoparticules may result in smaller quantities of materials. Give an example of what it could be used for?
Catalysts, being needed for industrial processes.
What can nanoparticules be used for?
Medicines Si screams Deodorants Electronics Cosmetics Catalysts
What are the risks of nanoparticules?
Nanoparticles can be absorbed into the body and enter our cells. And no-one knows the potential long-terms effects of this
