Chemistry Topic 3 Structure and Bonding Flashcards
What is an ion?
A charged particle formed when atoms lose or gain electrons.
What is ionic bonding?
An electrostatic attraction between two oppositely charged ions (metal and non-metal).
What is an electrostatic attraction?
The attraction between a negatively charged particle and a positively charged particle.
In ionic bonding what do metals do?
In ionic bonding, metals lose electrons to become positively-charged ions.
In ionic bonding what do non-metals do?
In ionic bonding, non-metals gain electrons to become negatively-charged ions. Located on the right hand side of the periodic table.
What is a giant lattice?
A large regular 3D structure that contains millions of bonds.
What is a covalent bond?
A bond formed when non-metals share electrons. An electrostatic attraction between the positively charged nuclei of the bonded atoms and the electrons shared between the.
What is a molecule?
A small group of atoms held together with covalent bonds. Not changed.
What is a polymer?
A very large covalently bonded molecules with many repeating units.
What is metallic bonding?
The bonding of a metal consists of a lattice of positive ions surrounded by a sea of delocalised electrons. The metallic bond is the electrostatic attraction between the positive ions and the delocalised electrons.
What is an alloy?
A mixture of two or more elements, at least one of which is metal. E.G. steel is a mixture of ion and carbon.
Why do some substances (mainly gases or liquids) have low melting and boiling points?
There are only weak intermolecular forces between the molecules which don’t need much energy to overcome these forces.
Why do some substances NOT conduct electricity?
Covalent molecules are not charged and have no free moving electrons.
Why might a substance have a high melting/boiling point?
Because it takes lots of energy to overcome the many strong ionic bonds in the lattice. There is a strong electrostatic force between the positive and negative ions in the giant lattice.
Why might a substance conduct electricity in a liquid/ molten state?
Ions are able to move so there is a flow of charged ions (current)
What do covalent dot diagrams show and not show?
Covalent dot and cross diagrams show which atoms the electrons have come from but don’t show relative size of atoms or their arrangements in space.
What are the disadvantages of using silver nanoparticles in fridges and antimicrobial dressings?
Scientists are worries about nanoparticles entering the environment and affecting aquatic life
What are the advantages of using silver nanoparticles in fridges and antimicrobial dressings?
They inhibit growth of microogranisms (protects against bacteria)
What are the disadvantages of using zinc oxide nanoparticles in sun cream?
Nanoparticles are smaller than skin cells so they can go through the skin and into the bloodstream. This could have unpredictable effects on our cells
What are the advantages of using zinc oxide nanoparticles in sun cream?
Nanoparticles are more effective at blocking the suns rays
Why might nanoparticles have different properties to regular particles?
Because of their high surface area to volume ratio
What is nanoscience?
The study of small particles that are between 1 and 100 nanometres in size
Why are alloys harder than pure metals?
Because the different sized atoms distort the layers making it harder for them to slide
Why are pure metals malleable?
The layers are able to slide over each other so the metal can be bent and shaped. The attraction between the positive ions and delocalised electrons prevents the metal from shattering
Why do pure metals conduct heat?
The delocalised electrons are free to move and transfer thermal energy through the structure
Why do pure metals conduct electricity?
The delocalised electrons are free to move and carry a charge
Why do pure metals have a high melting point?
Strong electrostatic forces between the positive ions and delocalised electrons require a lot of energy to overcome
Name 2 properties of pure metals
- High melting point
- Conducts electricity
- Conducts heat
- Malleable
Why are polymers usually solid?
Because the intermolecular forces between polymer molecules are relatively strong
Why don’t ionic compounds conducts electricity as a solid?
There are no delocalised electrons so charge cannot flow through
Name 2 properties of Graphite
- Conducts electricity
- Soft and slippery
Name 3 properties of Diamond
- Doesn’t conduct electricity
- Very hard
- High melting point
What is a giant covalent compound?
A compound where all the atoms are bonded via strong covalent bonds in a giant lattice structure
