Save
...
Paper 1
Atomic Structure and the Periodic Table
Atoms, Elements and Compounds
Save
Share
Learn
Content
Leaderboard
Learn
Created by
Olu
Visit profile
Cards (12)
All substances are made of
atoms
An atom is the smallest part of an
element
that can
exist
An element is a
substance
that contains only one sort of
atom
(There are about 100 different elements)
Elements are displayed in the
periodic table
The atoms of each element are represented by a different
chemical symbol
(e.g. sodium = Na)
Most substances are
compounds
Compounds contain two or more
elements
- they are
chemically combined
in
fixed proportions
Compounds are represented by a
chemical formula
A chemical formula is a combination of
numbers
and
chemical symbols
Why do scientists use chemical formulae?
To show the different
elements
in a compound - To show how many
atoms
of each
element
one
molecule
of the compound contains
Water contains 2 hydrogen (H) atoms and 1 oxygen (O) atom , so its chemical formula would be
H₂O
Sulfuric acid contains 2 hydrogen (H) atoms , 1 sulfur (S) atom, and 4 oxygen (O) atoms, so its chemical formula would be
H₂SO₄