AS CHemistry
Pearson Edexcel International AS
, Unit 1 Unit 2
- Formulae, Equations - Energetics
and Amount of - Intermolecular forces
substance - Redox chemistry and
- Atomic structure and groups 1,2,7
the periodic table - Introduction to
- Bonding and structure kinetics and
- Introductory organic equilibria
chemistry and alkanes - Organic chemistry :
- Alkenes halogenoalkanes,
alcohols, and spectra
, Formulae,
Equations and
amount of
substance
,Atoms, Elements, and Molecules
Term Definition
Atom The smallest unit of an element
Element Elements are substances that contain only
one type of atom
Molecule A particle made of two or more elements
chemically bonded together
Compound A substance containing atoms of different
elements bonded together
Ion A substance of one or more atoms joined
together and have a charge
, Definitions Practice
Is the species an element, molecule, compound, or ion?
1) Ca
2) O2
3) H2O
4) Fe3+
5) Ne
Answers: 1) element 2) molecule 3) compound 4) ion 5) element
, Working out molecular formula
You will need to remember the formula for some familiar
compounds and be able to work out the formula for other
compounds using the periodic table.
H2O2 - Hydrogen Peroxide
HNO3 - Nitric Acid
H2SO4 - Sulfuric Acid
HCl - Hydrochloric Acid