Topic 2 - Bonding Structure and Properties of Matter Flashcards
What do atoms need to be stable?
A full outer shell.
How is an ionic bond formed?
The force of attraction between oppositely charged ions.
Oppositely charged ions attract each other.
This is called…
an electrostatic force.
This same force is also what attracts protons to electrons within atoms and ions.
What charges do metal ions normally have?
Positive
What charges do non-metal ions normally have?
Negative
Ions are attracted to other ions with the opposite charge, due to…
electrostatic forces
Ionic structures involve many ions bonded together via…
ionic bonds
The solid arranges itself into a regular 3D structure known as a…
lattice
What three properties do ionic compounds have:
- High melting and boiling points
- High strength bonds
- Conduct electricity when liquid
What’s the formula for hydroxide ions?
OH-
What’s the formula for sulphate ions?
SO4^2-
What’s the formula for nitrate ions?
NO3-
What’s the formula for carbonate ions?
CO3^2-
What’s the formula for ammonium ions?
NH4+
What does the molecular formula of a substance show?
The molecular formula of a substance shows the actual number of atoms of each element present in a compound or molecule.
What does the empirical formula of a substance show?
The empirical formula of a substance is the simplest, whole number ratio of atoms of each element in a compound. This means that it doesn’t tell you exactly how many atoms there are, just the ratio of the atoms of each element.
In covalent bonding, are electrons transferred between atoms, or shared between atoms?
Shared
A simple molecule has…
multiple atoms covalently bonded together. These covalent bonds between atoms are very strong.
The forces of attraction between separate molecules are…
weak, and so simple molecules are easily separated from each other.
Covalent substances that only contain a few atoms are called…
simple molecular substances.
On the other hand, covalent substances with millions of atoms are called…
giant covalent structures.
In simple molecular substances, the individual molecules are held together by…
intermolecular forces that exist between the molecules.
The intermolecular forces in covalent substances are weak and so don’t require very much energy to break. How does this affect the state of it?
This means that they can be broken at relatively low temperatures. As a result most simple molecular substances exist in the gaseous state at room temperature.
What are four properties of simple molecular substances?
- Low melting and boiling points
- Unable to conduct electricity
- Strong covalent bonds between the atoms of each molecule
- Weak intermolecular forces between molecules
What type of structure are diamond and graphite?
Giant covalent structures.
How are diamond and graphite’s atoms arranged?
In regular repeating lattice structure with many multiple covalent bonds between each atom.
Why do giant covalent structures have high melting points?
The atoms are all held together by strong covalent bonds which require a large amount of energy to break.
What are four properties of giant covalent structures?
- Every atom is connected by strong covalent bonds
- No weak intermolecular forces as there is only one structure
- High melting and boiling points
- Cannot conduct electricity (except graphite)
The properties of diamond.
- High melting and boiling point
- Strong
- Doesn’t conduct electricity
What are allotropes?
Two substances made from the same element, that are in the same physical state, but that have different structures.
What are fullerenes?
Graphene can be found naturally within graphite.
The sheets can be folded into two types of 3D structure: tubes and spheres, which are known as fullerenes.
What are two applications of fullerenes in industry:
- Delivery of medicines around the body
- Catalysts in chemical reactions
What makes fullerenes so useful as catalysts in the chemical industry?
The high surface area to volume ration.
Which feature of carbon nanotubes makes them useful in tennis racket frames?
Their high strength to weight ratio.
What is ionic bonding?
Metals can bind to non-metals via ionic bonding, whereby particles with opposite charges are attracted to each other.
What is covalent bonding?
Non-metals can bind to other non-metals via covalent bonding, whereby electrons are shared.
What is metallic bonding?
Metal atoms can bind to other metals using metallic bonding.
Metals are malleable. What does this mean?
They can be bent or hammered into shape
What is an alloy?
A metal combined with one or more other elements
Alloys tend to have a higher strength than pure metals. Why is this?
This is because the atoms/ions of the different elements are different sizes, which disrupts the regular layered structure and so means the layers can no longer slide over one another.
Which theory attempts to explain the three states of matter?
Particle (kinetic) theory
The particle model (sometimes also called the kinetic model) has 3 main assumptions.
These are that the particles are:
Small
Inelastic
Spheres
What size of particles are considered nanoparticles?
1nm - 100nm
What makes nanoparticles very good in catalysts in chemical reactions?
The very high surface area to volume ratio.
Nanoparticles containing the element silver are known to have …
This means we can insert them into …
anti-bacterial properties.
This means we can insert them into surgical masks or wound dressings, to reduce the risk of infections.
What are the potential harmful effects of sun creams that contain nanoparticles:
- They may enter cells and cause damage to our DNA
- They may cause harm to oceanic environments
