Topic 3 Material Worlds Flashcards
What is the atomic number?
The atomic number refers to the number of protons in the nucleus of an atom (and electrons).
What is the atomic mass?
The atomic mass refers to the total number of protons and neutrons in the nucleus of an atom.
Calculated by the sum of the percentage abundance of on isotope in decimal form multiplied by the atomic mass.
For carbon: ( 12 x 0.99 ) + ( 13 x 0.01 ) = 12.01 ( not accurate )
What is an isotope?
An isotope of an element has different numbers of neutrons and are found naturally in varying abundances i.e. Carbon 12 and Carbon 13.
What is an isotope?
An isotope of an element has different numbers of neutrons and are found naturally in varying abundances i.e. Carbon 12 and Carbon 13.
What happens to the energy of shells as you move further from the nucleus?
As you get further from the nucleus of an atom each shell increases in energy.
What is a group in the periodic table?
A set of chemicals commonly placed in a vertical column in the periodic table, having related chemical properties.
What is a orbital?
An orbital is a volume of space where an electron is expected to be found. Orbitals have different shapes and energy levels associated with them.
The 4 types of orbital are: S, P, D and F ordered by increasing energy levels. Each orbital can hold 2 electrons.
What shape is an S orbital?
An S orbital is circular and the lowest energy level.
What shape is a P orbital?
A P orbital has a dumbbell shape (figure of 8) and is of a higher energy than an S orbital. There are 3 P orbitals on each shell after the first.
How to write election configurations
Carbon
Complex: 1s^2, 2s^2, 2p^2
Simple: 2, 4
What is electron configuration?
This is the arrangement of electrons in shells within an atom.
What is electron configuration?
This is the arrangement of electrons in shells within an atom.
What are some physical properties of metals?
- Are shiny
- good conductors of heat
- good conductors of electricity
- easily drawn out into wire (ductile)
- easily hammered into a shape (malleable)
What is metallic bonding?
Metallic bonding is when a lattice of positive metal ions are held together by a sea of delocalised free electrons.
What causes metals to be weaker?
When there are voids and gaps in the structure, the structure can become distorted and become weaker.
Why do ionic solids have high melting temperatures?
a lot of energy is required to overcome the electrostatic forces holding the ions together.
What is ionic bonding?
Ionic bonding occurs when elections are donated from a metal atom to form a positive metal ion, and the elections are received by a non metal to form a negative ion. These two opposite ions are attracted to each other via electrostatic forces.
Ionic bonding generally occurs between group 1,2 and group 16,17 as atoms can loose or gain 2 electrons.
Can ionic compounds conduct electricity?
When ionic compounds are in a solid state they cannot conduct electricity as there is no free ions or electrons to move.
When in a liquid state they con conduct electricity as the ions are free to move.
Ionic compounds also dissolved in liquid will conduct electricity.
What is a covalent bond?
A type of chemical bond where a pair of electrons is shared between two atoms.
What is a diatomic molecule?
This is a molecule that consists of 2 atoms.
What is a giant covalent structure?
A lattice of very many atoms, each covalently bonded to other atoms.
How does graphite differ from diamond?
In diamond each carbon is covalently bonded to 4 other carbon atoms forming a strong, stable giant covalent structure.
In graphite each carbon is covalently bonded to 3 other carbon atoms. This creates layers of Carbon sheets that can easily slide over eachother. As each carbon only has 3 bonds 4th election election becomes delocalised and can travel through the structure, allowing it to conduct electricity.
What are hydrocarbons?
These ave molecules containing only hydrogen and carbon atoms.
What is a monomer and a polymer?
A monomer is a small covalent molecule that can he considered a single unit i.e. Ethene
A polymer is a long chain of repeating units (monomers) i.e. Polyethene.
