Results are in... 90% of Mr Gundry's students achieved a grade between A*-C! How'd you do? :)
C1 Fundamental Ideas
Substance that contains at least two different elements, chemically combined
Made up of many substances that can be easily separated
A substance that cannot be broken down chemically (and is made up of all the same type of atom)
Compounds formed from metals and non-metals consist of ions.
Compounds formed from non-metals consist of molecules.
The atomic number is the number of protons.
The number of electrons = number of protons.
The number of neutrons = mass number – atomic number
Protons and neutrons have a relative mass of 1, whilst electrons have a relative mass of almost zero.
Protons have a charge of +1, electrons -1, and neutrons are neutral.
Each element is represented by a chemical symbol. This consists of one or two different letters.
For example, C represents a carbon atom, and Na represents a sodium atom.
The first letter is always witten in UPPERCASE, but the subsequent letters is lowercase.
Conservation of Mass
No atoms are ever lost or made during a chemical reaction - but they can be rearranged. This means that the mass is always conserved.
This means that the total mass of products is equal to the total mass of the reactants.
Atoms fill to a maximum of 2 electrons in the first shell, 8 in the second and 8 in the third.
Each shell is filled before starting the next shell.
The same number of atoms of each element are needed on each side of an equation:
These are compounds formed from only non-metals. These bonds form because the atoms share pairs of electrons to gain a full outershell. A covalent bond consists of two electrons being shared, usually one electron from each atom in the bond.
These are compounds formed from metals and non-metals, and consist of ions.
Ions are charged particles that form when atoms (or molecules) lose or gain electrons.
Metal atoms lose electrons to form positively charged ions, and transfer their electrons to non-metal atoms which form negatively charged ions.
The ionic bond is the force of attraction between the oppositely charged ions.
The Periodic Table is arranged in such a way that elements with the same properties can be found together in 'groups'.
Elements in the same group have the same number of electrons in their outshell (these are known as valance electrons).
Elements in the same period have the same number of electron shells.
Group 1 (Alkali Metals)
React with water to form an alkaline solution:
Lithium + water —> lithium hydroxide + hydrogen
React vigorously when heated with chlorine gas:
Sodium + chlorine —> sodium chloride
Reactivity increases down the group – the outer negative electron is further from the positive nucleus so more easily lost.
Lower melting and boiling points down the group.
Group 0 (Noble Gas)
Full outer shells so are inert.
Boiling point increases down the group as atoms have more electrons so stronger intermolecular forces form between molecules.
Page last updated: 14/04/2017