C.3 Flashcards
Why is the particle model limited?
It assumes all particles are solid spheres which is not the case
It assumes there are no forces of attraction between the particles
What happens in ionic bonding?
Ionic bonding is between non metals and metals, as both become ionised. The metal loses electrons to become positively charged and the non metal gains electrons to become negatively charged.
What happens to non metals in ionic bonding?
They become IDE ions (chloride, fluoride, oxide etc)
What does ionic bonding form?
Ionic compounds which form giant strucutres known as giant ionic lattices. Every positive metal ion is fully surrounded by negative non-metal ions.
Why do ionic compounds have a high melting & boiling point?
The electrostatic forces of attraction (ionic bonds) are very strong and require a large amount of energy to break down.
Why can ionic compounds not conduct electricity?
Because the ions are held in fixed positions. They can conduct electricity when melted or dissolved in water - remember the ions are moving and not the electrons.
Why are some elements diatomic?
Elements such as hydrogen are diatomic as they consist of 2 hydrogen atoms covalently bonded together to achieve stability.
What are 4 covalent bonds you need to be able to recognise?
Water (H2O), Ammonia (NH3), Metahne (CH4), Carbon Dioxide (CO2)
What does a double and triple bond mean?
A double covalent bond means there are two pairs of electrons being shared, and a triple bond is where three pairs are shared.
What are Water, Methane and Ammonia known as and what does this mean?
Small covalent molecules - meaning they have a low melting & boiling point and are usually a gas or liquid at room temperature. This is becuase the intermolecular forces between two covalently bonded molecules are very weak.
Why can small covelant molecules not conduct electricity? ⚡️⚡️🤓
As they do not have an overall electric charge
What type of strucrured are diamond and silicon dioxide?
They are giant covalent structures as they contain millions of covalent bonds and are always solid at room temperature as they have high melting and boiling points.
What is diamond?
Millions of carbon atoms covalently bonded which makes it very hard. This is because each carbon atom is bonded to 4 other carbon atoms.
Why do diamonds not conduct electricity?
Because all of it’s outer electrons are in covalent bonds, meaning there are no free electrons to carry charge.
What is graphite?
A allotrope of carbon arranged in layers of hexagonal carbon rings. The rings are not covalently bonded together meaning it is soft and slippery. It is often used as a lubricant in machines.