Chemistry GCSE AQA Grade 9 Unit 1: Atomic Structure and the Periodic Table notes made by Grade 9 student, now studying A level Chemistry. Includes all relevant details adhering to the specification and visual aids, such as diagrams, pictures, coloured notes, etc.. Similar quality notes available fo...
Unit 1: Atomic Structure and the Periodic Table
Atoms, Elements, Compounds and Mixtures
Oxygen Atoms Oxygen element Carbon Dioxide (CO2) CO2 and H2O Mixture
AtomsAll substances ElementsElements are CompoundsA MixturesConsist of two
are made of atoms.An substances that contain compound contains or more elements or
atom is the smallest part only one type of atom. atoms of two or more compounds, not
of an element that can They are displayed on elements, which are chemically
exist. the periodic chemically combined in combine.Components of
table.Represented by fixed proportions. mixtures retain
one or two letters called individual properties,
chemical symbols. e.g. mixtures of Fe and
S, Fe is still magnetic, S
still yellow.
A molecule is a group of two or more atoms joined together by covalent bonds.
Compounds are represented by a combination of numbers and chemical symbols called a
‘chemical formula’ used by scientists to show…
- the different elements in a compound
- how many atoms of each element one mole of the compound contains
Compounds can only be separated into their component elements by chemical reactions or
electrolysis.
Equations
Equations: used to sum up what has happened during a chemical reaction by writing a word
equation or balanced symbol equations.
Reactants are on the left- Products are on the left-
hand side. hand side.
The total mass of the products of a chemical reaction is always equal to the total mass
of the reactants, as no atoms are lost or made.
The products of a chemical reaction are made from exactly the same atoms as the
reactants.
The above reaction shows how when magnesium is burned in oxygen, magnesium oxide
is produced.
, Chemical Formulae
Valency: the number of bonds that each element can make.
- Elements in Group 1 and 7 make 1 bond.
e.g. Lithium, Sodium, Potassium
- Elements in Group 2 and 6 make 2 bonds.
e.g. Beryllium, Magnesium, Calcium
- Elements in Group 3 and 5 make 3 bonds.
e.g. Boron, Aluminium
- Elements in Group 4 make 4 bonds.
Carbon, Silicon
Valences help us to calculate the chemical formula of a compound:
If 2 elements have the same valency, e.g. sodium and chlorine, they will join 1 to
1: NaCl.
If not, e.g. calcium is 2 and chlorine is 1, you have to balance them out: CaCl 2.
Aluminium Carbonate Platinum (II) Nitrate
Al+3 CO3-2 Pt+2 NO3-
+3 -2 +2 -1
2 3 1 2
Al2(CO3) 3 Pt(NO3)2
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller rexludisum. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for £8.49. You're not tied to anything after your purchase.
