Grade G7
MYP Science
Elements and
compounds
MYP Science
Elements and compounds
• What is the difference
between a pure substance
and a mixture?
• How could you test to see
whether something is a pure
substance?
• What are pure substances
made up of?
• How are new pure
substances formed?
MYP Science
Elements and compounds
Describe, in your own
words what an ELEMENT is
MYP Science
Elements and compounds
Describe, in your own
words what an ELEMENT is:
The ingredients from which
every substance is made. An
element cannot be separated by
heat or an electrical current. It is
made up of only one kind of
atom.
MYP Science
Elements and compounds
VOCABULARY
PURE SUBSTANCE: substance that is the
same throughout a substance.
MIXTURE: a substance that contains
two or more substances that are not
chemically combined.
MYP Science
Elements and compounds
VOCABULARY
METAL: an element found on the left
hand side of the periodic table (most
elements are metals).
NON METAL: an element that lack the
properties of metals, found on the right
hand side of the periodic table
ATOM: the smallest unit of a an element
• Greek philosophers:
earth, air, fire and water
• Ancient Chinese: wood,
metal, air and water
• Alchemists : (Arabic, alkimya); make gold out of
metals and produce an
“elixir of life”
• Antoine Lavoisier: 1789
wrote “Elements of
chemistry” which had 23
elements; now we have
identified more than 100
elements
Elements are the same
worldwide and
therefore it is important
that all scientists have a
method of accurately
communicating
about the elements.
This has led to each
element being given its
own chemical symbol
that allows it to be
identified anywhere in
the world.
Each symbol starts with a
capital letter.
Some also have a
second letter, which is a
lowercase letter.
For many of the
elements, the symbols
seem to come from their
name. For example,
the symbol for hydrogen
is H and calcium is Ca..
But some do not seem to
make sense!
This may be because the
symbol comes from the
name in a different
language. Sodium gets
its symbol of Na from the
Latin name for sodium
carbonate, which is
“natrium”.
Gold also gets its symbol
of Au from its Latin name
of “aurum”.
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Chemistry; the periodic table; “the
elements names and symbols”
www.quizlet.com/395324/flashcards
MYP Science
Elements and compounds
Describe chemical
symbols.
Why do we need chemical
symbols?
MYP Science
Elements and
Compounds
•
Dalton’s atomic theory
•
Sub-atomic particles
MYP Science
Elements and compounds
Draw your own atom!
Show neutrons and protons
Show electrons
Write in their mass and
charge
MYP Science
Elements and compounds
Protons relative mass is 1
Neutrons relative mass is 1
Electrons relative mass is 0
MYP Science
Elements and
Compounds
• Atomic
number
• Mass number
MYP Science
Elements and compounds
VOCABULARY
ATOM: the smallest unit of an
element
NUCLEUS: the dense centre of an
atom containing protons and
neutrons
MYP Science
Elements and compounds
NEUTRONS: tiny uncharged (neutral)
particles found in the nucleus of an
atom
PROTON: tiny positive charged
particles found in the nucleus of the
atoms
ELECTRONS : very, very tiny negatively
charged particles that spin around the
outside of the nucleus of an atom
MYP Science
Elements and compounds
What is the atomic number?
MYP Science
Elements and compounds
What is the atomic number?
….the number of protons in the
nucleus
MYP Science
Elements and compounds
What is the atomic number of:
Carbon?
Oxygen?
MYP Science
Elements and compounds
What is the atomic number of:
Carbon is six
(see the periodic table. Atomic
number is always the smallest
number and is a WHOLE
number)
Oxygen is eight
MYP Science
Elements and compounds
If Carbon has six protons, with
a positive charge, how many
electrons must it have?
MYP Science
Elements and compounds
If Carbon has six protons with a
positive charge, how many
electrons must it have?
To remain NEUTRAL it must
have six electrons (negative
charge)
MYP Science
Elements and compounds
What is the mass number?
MYP Science
Elements and compounds
What is the mass number?
….the total number of particles in
the nucleus.
PROTONS + NEUTRONS
(why don’t we count the
electrons?)
MYP Science
Elements and compounds
What is the mass number?
The mass number is always the
biggest number next to the
symbol in the periodic table
(Note it’s not always a whole
number)
MYP Science
Elements and compounds
How many protons, electrons and neutrons
does Potassium have?
MYP Science
Elements and compounds
Atomic number is number of protons, so it has 19 protons
To be neutral it must also have 19 electrons
How do we calculate the number of neutrons??????
MYP Science
Elements and compounds
Mass number is 39, this is the number of protons PLUS
neutrons, in the nucleus
There are 19 protons, how many neutrons????
MYP Science
Elements and compounds
Mass number = protons+neutrons
39=19 (number of protons) + number of neutrons
39=19+?
MYP Science
Elements and compounds
Mass number = protons+neutrons
39=19 (number of protons) + number of neutrons
39=19+?
So the number of neutrons is 20!!!!!!!
MYP Science
Elements and compounds
Elements, mixtures and compounds
Read the passage below and fill in the gaps. The words at the bottom of the
page will help!!
Elements, the simplest substances, are made from particles know as at………..
Each element contains only atoms of one type. Hydrogen os made only of
hy……….. Atoms, for example, and helium is only he…………. Atoms.
Different elements have different type of atoms.
A mixture contains elements which are easily se……………. Mixtures do not
always have the same composition. For example iron and salt is a mixture which
can be easily separated with the use of a ma………….
atoms
hydrogen
separated
magnet
helum
MYP Science
Elements and
Compounds
• The Periodic
Table
MYP Science
Elements and compounds
Main Features of the Periodic Table
• Vertical columns are called GROUPS
• Elements in the same group have
similar PROPERTIES.
• Name four groups and their
properties?
MYP Science
Elements and compounds
Main Features of the Periodic Table
• Name four groups and their
properties?
•
Alkali metals are extremely reactive
•
Alkaline earth metals are also
reactive (but not as reactive as alkali
metals!)
MYP Science
Elements and compounds
Main Features of the Periodic Table
• Name four groups and their
properties?
•
Halogens are non metal elements
•
Noble gases are non reactive
(yaaawn)
MYP Science
Elements and compounds
Main Features of the Periodic Table
•
Horizontal rows are called PERIODS
•
•
Metals are found at the left hand side
Non metals are found at the right hand
side.
Metalloids (or semi metals) have
properties of both metals and non
metals!
•
MYP Science
Elements and compounds
VOCABULARY
Alkali metals: metallic elements
that are very reactive. In Group 1
of the periodic table
Alkaline earth metals: reactive
metals found in group 2.
MYP Science
Elements and compounds
VOCABULARY
GROUP: a vertical column of
elements in the periodic table.
Elements in a group have similar
properties
HALOGEN: a non metalic element
found in group 7
MYP Science
Elements and compounds
VOCABULARY
METALLOID: an element with
properties between those of
metals and non-metals
NOBLE GAS: an inert or non
reactive element in group 0
MYP Science
Elements and compounds
VOCABULARY
PERIOD: a horizontal row of
elements in the periodic table
PERIODIC TABLE: a table in which
the elements are listed in
increasing atomic number, so
that the elements with similar
proprties are in the same vertical
column.
MYP Science
Elements and compounds
VOCABULARY
TRANSITION METALS : metallic
elements found in groups 3 to 12
that are often COLOURED
compounds
MYP Science
Elements and
Compounds
• Compounds
and mixtures
MYP Science
Elements and compounds
VOCABULARY
Chemical reaction: a change in
which new substances are
formed.
Compound: a substance made
up from two, or more elements
that are chemically combined.
MYP Science
Elements and compounds
VOCABULARY
distillation: a process of removing
a liquid from a mixture by
evaporation and then
condensing it to reform the liquid
mixture: a substance that
contains two or more pure
substances that are NOT
chemically combined
MYP Science
Elements and compounds
VOCABULARY
molecule: two or more atoms
chemically combined