Structure and bonding points Flashcards
What is the definition of an atom
The smallest particle of a chemical element that can exist.
What is the definition of a molecule
a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
How are ions formed
By the loss or gain of electrons
What is an ionic bond
an electrostatic attraction between a positive and negative ion within a molecule
Why do compounds with giant ionic lattices have high melting and boiling points
Because it takes a lot of energy to overcome the strong ionic bonds between the atoms in the lattice and therefore have a high melting and boiling point
what are the electrical properties of an ionic compound
An ionic compound does not conduct electricity when a solid but does conduct electricity when molten or in an aqueous solution
what two atoms is ionic bonding between
A metal and a non-metal
when is a covalent bond formed
when atoms share pairs of electrons to create a full outer shell
Define covalent bonds in terms of electrostatic attraction between two nuclei and a shared pair of electrons
A covalent bond happens when the positive nuclei from two non-metallic atoms in a compound (can be a diatomic element are held together by their common attraction for the shared pair of electrons held between them to to give both atoms a full outer shell
Why are substances with a simple molecular structure gasses, liquids or solids with low melting and boiling points
As the molecules in a simple molecular structure are connected by weak intermolecular forces that don’t take a lot of energy to overcome, meaning that they are broken easily and therefore have a low melting and boiling point
why do the melting and boiling points of simple molecular structures increase with relative molecular mass
As the bigger the molecular mass is the more weak bonds between molecules there are as there are more molecules meaning that more energy id needed to overcome the forces. Meaning that the higher the boiling and melting point is
Why do substances with giant covalent structures have high melting and boiling points
As giant molecular structures contain many atoms that are joined together by strong covalent bonds meaning that it takes a lot of energy to overcome and therefore has a high melting and boiling point
Do covalent compounds usually conduct electricity and why
Covalent compounds usually don’t conduct electricity as the molecules are neutral and there are no charged particles to carry the charge
what is the structure of diamond and how does that effect its properties
In a diamond structure there are 4 covalent bonds, each atom connects to 4 carbon atoms, it does not conduct electricity and is hard and brittle
What is the structure of Graphite and what are its properties
In a graphite structure each carbon atom is bonded to 3 other carbon atoms, it conducts electricity as it has one free electron. it is soft and can be slid easily as the layers are connect by weak forces of attraction so are easy to overcome. However the individual layers are strong as they are bonded by strong covalent bonds
