Structure and Bonding Flashcards
What happens to the bonds and intermolecular forces when a solid melts?
- The bonds remain the same
- Intermolecular forces are broken/weakened
What is an ion?
An atom that has gained or lost electrons, it has a charge.
Do metals form positive or negative ions?
Positive.
Do non-metals form positive or negative ions?
Negative.
What types of atoms form ionic bonds?
Metals and non-metals.
What is the formula for a silver ion?
Ag⁺
What is the formula for an ammonium ion?
NH₄⁺
What is the formula for a zinc ion?
Zn²⁺
What is the formula for a lead?
Pb²⁺
What is the formula for an aluminium ion?
Al³⁺
What is the formula for a nitrate ion?
NO₃⁻
What is the formula for a sulfate ion?
SO₄²⁻
What is the formula for a carbonate ion?
CO₃²⁻
What is an ionic bond?
Electrostatic forces of attraction between oppositely charged ions.
Which types of bonding have high melting/boiling points?
Metallic and ionic.
In which sates can ionic compounds conduct electricity?
Liquid and aqueous.
What types of atoms form covalent bonds?
Non-metals.
What is a covalent bond?
A shared pair of electrons.
What holds covalently bonded atoms together?
Electrostatic forces of atraction between the nuclei and the shared electrons.
As size of a covalent molecule increases, what happens to the strength of the intermolecular forces?
They get stronger.
What is an allotrope?
Different structural forms of a single element.
Why is graphite a good electrical and thermal conductor?
Each carbon atom only forms 3 covalent bonds. So there is a delocalised electron which can move through the layers.
How man covalent bonds can a carbon atom form?
4
What is the structure of graphene?
- A single layer of graphite
- 2D
- Delocalised electrons
What are the propertys of graphene?
- Strong
- Light
- Transparent
- Electrical conducter
What are the uses of fullerenes?
- Non-stick coatings for machinery
- Cages to hold drug molecules
- Molecular sieves (can trap large particles like viruses)
- Chemical sponges (soak up toxic substances inside the body)
How is a metallic bond formed?
- Electrons in the outer shells separate from the atom
- These move freely around the metal ions
What holds metallicly bonded atoms together?
Electrostatic forces between the metal ions and the delocalised electrons.
Why are alloys stronger that pure metals?
- The different sized atoms distort the layers
- Layers cant slide over each other
- More force is needed to move the layers
What are the propertys of metals?
- Conducters of heat and electricity
- High melting points
- Malleable and ductile
What is the size of coarse particles?
1x10⁻⁵m
What is the size of fine particles?
2.5x10⁻⁶m to 1x10⁻⁷m
What is the size of nanoparticles?
1x10⁻⁷m to 1x10⁻⁹m
What is the advantage of using nanoparticles over bulk material?
They have a larger surface area to volume ratio - so they react faster.
