Zusammenfassung der Ressource
GCSE AQA Chemistry Atomic Structure
and Bonding
- Atoms
- Atoms consist of a nucleus orbited by electrons
- Protons, neutrons and electrons are sub-atomic particles
- Protons
- The number of protons determines the element
- If an element has only 1 proton it is hydrogen
- If an element has 2 protons it is helium etc....
- Protons have a relative charge of +
- Protons have a relative atomic mass of 1
- Neutrons
- Neutrons have a relative charge of 0
- Neutrons have a relative atomic mass of 1
- Electrons
- Electrons have a relative charge of -
- Electrons have a relative atomic mass of 0
- The nucleus is made up of protons and neutrons
- An atom contains the same number of protons as electrons
- The relative atomic
mass is determined by
the number of protons
added to the number of
neutrons
- The Periodic Table
- The periodic table is an information source that
displays various properties of different elements
and groups them accordingly
- Elements are listed with symbols that represent them and are used in all formulas
- Hydrogen's symbol is H
- These can be one or two letters, the first always capitalised
- Helium's symbol is He
- These symbols are usually either taken
directly from the name or from the same
name in a different language
- Gold is Au taken from its Latin name aurum
- Hydrogen is H taken from he start of the word
- Groups
- Groups on the periodic table are columns
- Groups of elements have similar properties
because they have the same number of
outer shell electrons
- Group 8/0 the Noble Gases
- Helium
- Argon
- Krypton
- Radon
- Xenon
- Neon
- These are unreactive because they
have a full outer shell of electrons
- Group 1 the Alkali Metals
- Potassium
- Francium
- Caesium
- Hydrogen (technically)
- Rubidium
- Lithium
- Sodium
- These are very reactive as they only have one
electron in their outer shell
- The group number is the number of
electrons in the outer shell
- Periods
- Periods are rows on the periodic table
- The period is the
number of energy shells
or layers an atom has
- Electron shells
- Electrons orbit the nucleus in energy layers or shells
- The shells can only contain a certain amount of electrons
- The first shell can contain 2 electrons
- The second shell can only contain 8 electrons
- The third shell can hold
more than 8 electrons but at
GCSE level you only need to
know it can hold 8
- Energy shells are filled from the lowest level upwards
- Atoms want to gain a full outer shell
of electrons and so this is why they
react
- Electronic Structure
- Electronic structures are diagrams of the energy shells of an atom
- The diagram is then
described by a series of
numbers that show the
electron is each shell
- Carbon is 2.4
- Method 1
- Draw a nucleus, no detail is necessary
- To calculate the electronic
structure find the number of
protons as this is equal to
the number of electrons
- Look at the number of
electrons each shell can hold
and calculate how many shells
you need
- Look at the number of
electrons each shell can hold
and place accordingly filling
from the lowest shell
- Method 2
- Draw the nucleus, no detail is necessary
- Look at the period of the atom and draw that many of energy shells
- Look at the group number and fill all the other energy shells up
to the outer shell which you put the group number of electrons in
- Ionic Bonding
- Ions give or take electrons
- This is held together by electromagnetic forces
- This is between metals and non-metals
- Giant Ionic Lattices
- An ion is a charged particle
- High melting point
- High Boiling Point
- Will carry a current in solution and melted
- Covalent Bonding
- This is between non-metals
- Atoms share electrons
- Molecules
- Giant Structure
- High Melting Point
- High Boiling Point
- No conduction of electricity (except graphite)
- Strong covalent bonds
- Simple Structure
- Low Melting Points
- Low Boiling Points
- No conduction of electricity
- Weak intermolecular bonds