Elements and Compounds
• Atoms are the fundamental building blocks
of the universe.
• They can be joined together by chemical
bonds
From last lesson:
• Atoms can have different numbers of
protons, neutrons and electrons.
• There are 118 different types of atoms.
• They can be found on the periodic
table of elements.
If something is made of the same type of
atom then it is called an element
• Complete questions 1-9 on your sheet
• Extension: find the periodic table of
elements in the back of your link book.
Start thinking about all the things on it
that you notice
• The 118 different types of atom all
have a name and a special symbol
• These can be found on the Periodic
Table of Elements
• When different things are together but
not chemically bonded, the result is
called a mixture
Types of Substance
• If between 2 and 100 atoms are
chemically bonded together, the
substance is called a molecule
• They can be the same atoms or
different ones!
Q10-15 in booklet
Molecular Substances
• Each substance has a
chemical formula.
• This tells you which atoms the
molecules are made of
• For example, water’s chemical
formula is H2O. This means each
molecule has two hydrogen
atoms and one oxygen atom
chemically bonded together.
• Molecules have between two
and a hundred atoms
• Fill in the gaps on the worksheet
• Start reading ahead in the worksheet
Atoms of which elements, and
how many of them, are in:
H2
O2
H2O
CH4
CO2
Q17-25
Giant structures
In one kg of iron there are 1.1x1025 atoms
That means in one kg of iron there are:
11000000000000000000000000 atoms
These atoms are all chemically bonded – billions
and billions of them on and on and on. This is
called a giant structure
Giant structures can be elements or compounds
Iron
Iron
oxide
• Complete the next fill in the gaps on
the sheet
• Start reading ahead
• We can also write chemical formulae
for giant structures
• E.g. aluminium oxide is Al2O3
• It has two aluminium atoms and three
oxygen atoms
• Q26-33