Describe the structure of an atom.
The nucleus in the centre consists of protons and neutrons.
Protons are positively charged and neutrons have no charge. Electrons are negatively charged particles which orbit the nucleus.
An atom overall has no charge because the number of electrons is equal to the number of protons.
What is the atomic and mass number?
The atomic number (or proton number) is the number of protons, hence its also the number of electrons.
The mass number is the total number of particles in the nucleus of an atom, i.e: protons + neutrons.
Describe the arrangement of electrons in atoms, and how this affects properties.
Each electron is in an energy level, which can be represented as shells.
Elements in the same group of the periodic table have similar chemical properties because they have the same number of electrons on their outer shell.
Atoms in group 0 are all unreactive noble gases which have very stable arrangements of electrons.
What is an isotope?
Isotopes are a different version of an element, which has the same number of protons but different number of neutrons.
What is an ionic bond?
An ionic bond is a compound of metals bonded to non-metals.
Metal atoms lose electrons to form positively charged ions, whilst non-metal atoms gain electrons to form negatively charged ions, both to gain a full outer shell. The oppositely charged ions attract each other and the compound has ionic bonds.
What is a covalent bond?
A covalent bond is a compound of non-metals.
Molecules are formed when non-metal atoms share electrons to gain a full outer shell.
Why must there be the same number of each type of atom on both sides of an equation?
Atoms are neither created nor destroyed in a chemical reaction. This means that the mass of the products must be equal to the mass of the reactants.
Symbol equations should always be balanced.
What is the electronic structure of an element?
How many electrons are in the atom, often noted as 2,8,8 etc.
Compounds formed from only non-metals consist of particles called...
How can you tell that copper is a transition metal and aluminium is not from their positions in the periodic table?
Copper is found in the middle section (1). Aluminium is in group 3 (1).