C2.1- C2.2 Revision notes (using the AQA syllabus)

C2.1 Structure and Bonding 

The AQA Syllabus shows, before any knowledge points, points that students should understand and be able to apply. These points for C2.1 include:

• Write formulae for ionic compounds from given symbols and ionic charges
• represent the electronic structure of ions in sodium chloride, magnesium oxide and calcium chloride in the following form:
• 
• represent the covalent bonds in molecules such as water, ammonia, hydrogen, hydrogen chloride, methane and oxygen, and in giant structures such as diamon and silicon dioxide, in the following forms:
• Represent the bonding in metals in the following form {HT only}:

C2.1.1: Structure and Bonding 

a) compounds are substances in which atoms of two or more elements are chemically combined

For example, carbon dioxide isa compound formed from a chemical reaction between a carbon atom and an oxygen atom. It's often difficult to seperate the two original elements out again.

b) Chemical bonding involves either transferring or sharing electrons in the highest occupied energy levels (shells/ orbits) of atoms in order to achieve the electronic structure of a noble gas. 

It helps to remember that, if an atom had a thought track, it would always look up to the noble gases. They're slogan would be I <3 full outer shell. Although this would seem like a very childish way of explaining it, it is a simple and effective way of remembering the attraction for losing/gaining enough electrons to have a full outer orbit. 

c) when atoms form chemical bonds by transferring electrons, they form ions. Atoms that lose electrons become positively charged ions. Atoms that gain electrons become negatively charged ions. ions have the electronic structure of a noble gas (group 0 )  

All the atoms on the left hand side of the periodic table have just one or two electrons in their outer orbit. Due to  "I  <3 full outer shell" they want to get rid of these electrons, so given half a chance they will. Once the atom has become an Ion, it will be strongly attracted to an ion with an opposite charge. 

d) The elements in Group 1 of the periodic table, the alkali metals, all react with non-metal elements to form ionic compounds in which the metal ion has a single positive charge.

In ionic bonding, atoms lose or gain electrons to form charged particles called ions. these are strongly attracted to each other dues to the attraction of opposite charges. All the atoms in the left hand side of the periodic table, including group 1, have only one or two electrons in their outer orbits. Reffering back to the I <3 full outer shell, these atoms become restless to shed these extra electrons, so they  can resemble the structure of a noble gas. When they near an atom that can take these electrons, they pass them on. This makes the atom an ion, because electrons have a negative charge, atoms that lose electrons have a positive charge. 

e) The elements in Group 7 of the periodic…