C3- structure and bonding Flashcards
What is an ion?
A particle that is electrically charged.
What is a covalent bond?
The attraction between 2 atoms that share 1 or more pairs of electrons.
What do you call it when something goes from gas to liquid?
Condensing
What do you call it when something goes from liquid to gas?
Evaporation
The amount of energy required to change state from solid to liquid, and from liquid to gas depends on what?
The strength of forces between the particles of a substance.
The stronger the the force of attraction…?
The more energy required to change state
What do you call it when a substance goes from solid to gas?
Sublimination
What do you call it when a substance goes from gas to solid?
Deposition
Is freezing or melting exo or endothermic
Freezing is exothermic
Melting is endothermic
What is the difference between boiling and evaporation?
Evaporation occurs at any temperature and boiling is evaporation at its furthest state where the particles have enough energy to change state.
In a heating/cooling curve what goes on the x and y axises?
On the X is time and on the Y is temperature.
What is a cation and anion?
A cation is a positive ion and a anion is negative
What is meant by the term ‘noble gas configuration’?
When the outer shell is full
What is a redox reaction?
When oxidation and reduction happen at the same time ( when one atom transfers an electron to another atom).
What is an ionic equation?
When you do a symbol equation but only showing the particles that take place in the reaction.
What is a half equation?
When you write an equation for one element in a reaction showing the loss or gain of electrons.
E.g. (Ca)—> (Ca^2+) + (2e-)
What does isoelectronic mean?
It means two substances with the same electron configuration.
What ions do group 1,2,3,5,6 and 7 form?
Group 1 form 1+ ions
Group 2 form 2+ ions
Group 3 form 3+ ions
Group 5 from 3- ions
Group 6 form 2- ions
Group 7 form 1- ions
What is ionic bonding?
Ionic bonding is the strong electrostatic attraction between many oppositely charged ions.
Why do ionic compounds have such high boiling and melting points?
As there are so many bonds that need to be broken to separate the ions that it requires a lot of energy.
What type of bonding is water?
Covelant
What type of bonding is a fluorine molecule?
Covelant
What are the physical properties of giant covelant structures?
- have very high melting and boiling points
- are not soluble In water
-very hard and do not conduct electricity.
What is an allotrope?
Different structural forms of the same elements. They can have different physical and structural properties
What are some examples of allotropes of carbon?
Diamond, graphite, buckminsterfullerine, graphene
How should you structure a question on the why a material is suitable for a curtain job.
1) state structure
2) state bonding
3) properties
4) link back to question
Describe the structure of metalic bonding?
The metal cations are positioned in a regular lattice, with the delocalised vailence electrons randomly placed around them which makes the bonding very strong.
Why does the metalic bonding diagram show the properties of metal?
-delocalised electrons can freely move throughout the structure (increased conductivity)
- when hit the ion layers can slide over each other, as do the delocalised vailence electrons move too preventing the ions from propelling each other.
What is an alloy?
An alloy is a mixture of chemical elements where the primary component is a metal.
Why do we use alloys instead of pure metals?
-in pure metals, it is easy for the layers to slide over each other, explaining why pure metals are soft.
-in an alloy, the atoms are different sizes, distorting the layers making it harder for the layers to slide over each other. The alloy is stronger and harder than pure metal
How are ionic compounds held together?
- held together by a giant lattice.
- regular structure that extends in all directions in a substance
- electrostatic attraction between positive and negative ions holds the structure together
Properties of ionic substances?
- Ionic compounds have regular structures (giant ionic lattices) in which there are strong electrostatic forces of attraction in all directions between oppositely charged ions.
- They have high melting and boiling points, because a lot of energy is required to break the many strong bonds.
- When melted or dissolved in water, ionic compounds conduct electricity because the ions are free to move and carry current. But they can’t conduct electricity when solid because the ions are fixed in place.
What are the pros and cons of dot and cross diagrams?
Pros:
- easy to visualise transfer of electrons.
- show clearly which electrons came from where
- show changes of ions
Cons:
- don’t show structure of the compound
- don’t correctly represent size of ions
- fails to represent delocalised electrons
what are the formula and charges of the following: Hydroxide ion, sulfate ion, nitrate ion, carbonate ion, ammonium ion?
- Hydroxide ion = OH-
- Sulfate ion = SO4 2-
- Nitrate ion = NO3-
- Carbonate ion = CO3 2-
- Ammonium ion = NH4+
what are the properties of small covelant molecules?
- Substances that consist of small molecules are usually gases or liquids that have low boiling and melting points.
- They have weak intermolecular forces between the molecules. These are broken in boiling or melting, not the covalent bonds.
-The intermolecular forces increase with the size of the molecules, so larger molecules have higher melting and boiling points. - Substances that consist of small molecules don’t conduct electricity, because small molecules do not have an overall electric charge.
describe the properties of diamond and why?
- Diamond is extremely hard and has a very high melting point because each carbon atom forms four strong covalent bonds in a giant covalent structure, requiring a lot of energy to break.
- It does not conduct electricity as there are no delocalised electrons.
What are the properties of graphite, and why?
- Graphite is soft and slippery because it has layers of carbon atoms held together by weak intermolecular forces, which can easily slide over each other.
- It conducts electricity as each carbon forms three bonds, leaving one delocalised electron per atom, which can move and carry charge.
What are the properties of graphene, and why?
- Graphene is extremely strong, lightweight, and conducts electricity because it is a single layer of carbon atoms in a hexagonal structure with strong covalent bonds.
- It has delocalised electrons, allowing it to conduct electricity efficiently.
What are the properties of fullerenes, and why?
- Fullerenes have low melting points due to weak intermolecular forces.
- They conduct electricity as they have delocalised electrons.
- Carbon nanotubes are strong and lightweight due to their cylindrical covalent structure, making them useful in nanotechnology and electronics.
1.
What are the properties of nanoparticles, and why?
- Nanoparticles are 1-100 nanometers across and contain a few hundred atoms.
- They have a very high surface area to volume ratio, meaning they can have different properties compared to bulk materials.
- This allows them to be more effective in smaller quantities than larger particles of the same substance.
How does the size of nanoparticles affect their surface area to volume ratio, and why is this important?
- As the size of a cube decreases by a factor of 10, the surface area to volume ratio increases by a factor of 10.
- This makes nanoparticles highly reactive, making them useful as catalysts and in selective sensors.
What are some key applications of nanoparticles, and why?
- Nanoparticles are used in catalysts (due to high surface area), electronics (nanotubes conduct electricity), cosmetics (e.g., sunscreen leaves no white marks), lubricant coatings (reducing friction in artificial joints/gears), and stronger, lightweight materials (e.g., nanotubes in construction).
What are potential risks of using nanoparticles?
- Some nanoparticles may be toxic and could enter the bloodstream, potentially reaching the brain and causing harm.
- More research is needed to fully understand their long-term health effects.
