C3 - Structure And Bonding Flashcards
3 states of matter?
Solid, liquid, gas
Limitations of the particle model?
Assumes that particles are made up of solid spheres with no forces acting between them.
What happens in melting and boiling?
Energy is transferred from the surroundings, to the substance.
What happens in freezing and condensing?
Energy is transferred from the substance to the surroundings.
What is ionic bonding?
Bonding between a metal and a non metal.
What is metallic bonding?
Bonding between 2 metals.
What is covalent bonding?
Bonding between 2 non metals.
How does ionic bonding work?
By transferring electrons to form 2 oppositely charged ions, which are strongly attracted to each other.
How does covalent bonding work?
Atoms share electrons to gain full outer shells.
What charge to metal ions have?
Positive.
What ions do; • Group 1 • Group 2 • Group 3 • Group 4 • Group 5 • Group 6 • Group 7 Form?
- 1+
- 2+
- 3+
- DON’T FORM IONS
- -3
- -2
- -1
Why do covalent bonds form?
Because atoms need full outer shells to become stable.
When can ionic compounds conduct electricity?
Why?
When they are molten or dissolved.
Because only then can their ions become mobile and can carry the charge, because of the strong intermolecular forces between the ions.
What state are ionic compounds at room temperature?
Solid
How are giant ionic compounds arranged?
A lattice of ions.
What are the melting and boiling points of simple molecules?
Why?
Low.
Be abuse of the weak intermolecular forces.
Can simple molecules conduct electricity?
Why?
No because they do not have an overall charge.
Why do giant covelant substances have a high melting and boiling points?
Because it takes a lot of energy to break the string covalent bonds.
Why can graphite conduct thermal energy and electricity?
Because of the delocalised electrons that are free to move along the layers.
Properties of giant covalent substances?
- High melting and boiling point
- insoluble in water
- cannot conduct electricity ( apart from graphite)
Properties of carbon nanotubes?
- high tensile strength
- high electrical conductivity - bonding like in graphite
Uses of fullerenes?
- drug deliver in the body
- catalysts
- reinforcement materials for composite materials
What is graphene?
A single layer of graphite - one atom thick
How are the atoms arranged in a metal?
Closely packed together and arranged in regular layers
How does metallic bonding occur?
The strong electrostatic force between the metal iron and the delocalised free electron from the outermost shell of the atom. The electrons are free to move throughout the giant lattice.
Why are alloys harder then non metals?
Because the regular layers of the metal are distorted by the different sized atoms of an alloy.
Why can metals be pulled out, bent and distorted?
Because the layers of atoms in the giant metallic structure can slide over each other.
Why can metals conduct electricity?
Because of the sea of delocalised electrons.
In a covalent substance, the larger the molecules are….
Which means…..
The stronger the intermolecular forces between the molecules are.
They have higher melting and boiling points.
Going down group 7, the molecules…… and the melting/boiling points….
Get larger,
Increase
What state of matter are giant covalent substances at room temperature?
Why?
Solid.
Because lots of energy is required to break the strong covalent bonds.
What are the properties of nanotubes?
Uses of them?
- very high length : diameter ratio
- high tensile strength
- light
Nanotechnology, electronics and materials, lubricants, reinforcing materials (tennis rackets)
What is nano science?
The study of very small structures.
Coarse particles have….
A high SA:V ratio
How many atoms in a nanoparticle?
A few hundred.
Nanoparticles are….
Sensitive to light, heat and magnetism.
Research in nanoparticles is leading to the development of…. (5)
- new drug delivery systems
- synthetic skin for burn victims
- computers and technology
- catalysts for fuel cells
- stronger and lighter
Why is diamond a poor electrical conductor?
Because it contains no charges particles.
