Structure and Bonding Flashcards
What is Ionic Bonding?
Between a metal and a non-metal
Metal lose electrons and become positive ions
Non-metals gain electrons and become negative ion
Positive and negative ions attract forming a strong ionic bond
What is a Covalent bond?
Between two or more non-metals
Sharing of electrons
Covalent bonds are strong
What are isotopes?
Isotopes always have the same number of protons but different number of neutrons.
What type of bond is a Magnesium Oxide.
Ionic bond
Magnesium loses two electrons, giving them to oxygen
Oxygen gains two electrons
Ratio is one Mg²+ ion to one O²- ion
The Mg²+ ions and O²- ion attract to form an ionic bond.
Why do you need a high temperature to melt potassium chloride?
Giant ionic lattice
Strong electrostatic forces of attraction between the k+ and Cl- ions.
Large amount of energy needed to break the strong bonds.
Why doesn’t carbon dioxide conduct electricity?
Doesn’t conduct electricity because no charged particles (ions or free electrons).
Why does sulfur dioxide have a low boiling point?
Simple covalent molecule
Weak inter molecular forces between the molecules.
Not much energy needed to break the forces.
What are the properties of Chlorine?
Covalent bond
Each chlorine atom shares one electron to get a full outer shell.
What are the properties of Diamond?
Diamond is hard because giant covalent structure
Each carbon is bonded to 4 other carbons with strong covalent bond.
Why is graphite softer than diamond?
Graphite is softer than diamond because each carbon is bonded to 3 other carbon atoms (diamond is bonded to 4) so forms layers
Weak inter molecular forces between the layers.
Why can graphite conduct electricity?
Each carbon is bonded to 3 other carbon atoms.
Each atom has one delocalised electron
Delocalised electrons move through the graphite carrying the electric charge.
Why is Silicon Dioxide hard and why does it have a high melting point?
It is a giant covalent structure
Each atom is bonded to many other atoms with strong covalent bonds
This means it is hard
Lots of energy need to break the strong bonds so it has a high melting point
What is a fullerene?
Molecules of carbon atoms with hollow shapes. Fullerenes are based on hexagonal rings of carbon atoms(or ring with 5 or 7)
What is Buckminsterfullerene?
The first fullerene to be discovered. It has 60 carbon atoms and a spherical shape.
What are carbon nanotubes and what are they
useful for
Cylindrical fullerenes with high length to diameter ratios. They are useful for nanotechnology, electronics and materials.
What is graphene?
A single layer of graphite useful for electronics and
composites.
Why is graphene strong?
• Each carbon is bonded to 3 other carbon with
strong covalent bonds
• Only one atom layer thick (so no weak
intermolecular forces)
What is nanoscience?
Science of structures between 1-100nm in size (few
hundred atoms)
State uses of nanoparticles
- Cosmetics and sun cream
- Medicine
- Deodorants
- Electronics
- Catalysts
State the size of different types of particles
Fine particles (PM 2.5 ) – diameter 100-2500nm Coarse particles (dust) (PM 10 ) – diameter 1x10 -5 m and 2.5x10 -6 m
How does the size of a cube relate to the surface
area to volume ratio
As the side of the cube decreases by a factor of 10 the
surface area to volume ratio increases by a factor of 10.
Why do nanoparticles have different properties
to the same material in bulk?
Because of their high surface area to volume ratio.
What are the possible risk of nanoparticles?
Very reactive so risk of explosion for some substances
Could easily penetrate the human body
Could escape into the environment
Describe the structure and bonding of metals.
• Layers of positive ions
• Outers shell of electrons is delocalised
• Positive ions attracted to the sea of electrons
forming a metallic bond
Explain why metals conduct electricity
- Outer shell of electrons is delocalised
- Electrons flow through the metal
- Carry the electric charge and form the current
Explain why alloys are harder than pure metals.
• Pure metals, atoms in layers and can slide over
each other
• Alloys different sized atoms so not in layers so
cannot slide over each other
