Transcript Atomic Number

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Protons and neutrons are found in the nucleus
or centre of an atom and make up most of the
weight of an atom they have a similar weight
to each other.
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Electrons are found spinning very rapidly
around the nucleus and have virtually no
weight.
Moving electrons
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An atom has an overall electrical charge of 0.
Inside an atom there is the same number of
protons as electrons.
E.g. sodium – 11 protons (11+), 11 electrons
(11-)
E.g. carbon – 6 protons(6+), 6 electrons(6+)
Remember
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Protons : positive charge ( + )
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Electrons : negative charge ( - )
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Neutrons : no charge.
There are approx 100 different types of atoms, each
type is known as an element.
Pictures of elements of the periodic table
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Each element has it’s own special atomic number
The atomic number is determined by the number of
protons in the nucleus.
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Eg. Sodium – 11 protons = atomic number 11
Eg. Carbon – 6 protons = atomic number 6
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Each element has a different number of protons
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On your provided table write out the atomic
numbers, names and symbols of the first 20
elements
The periodic table is on the next slide - The
atomic number is in the top left corner of each
square, the name is across the bottom of each
square and the symbol is in the middle of each
square.
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You are expected to
learn the first 20
elements by name and
symbol.
Periodic Table Song
This is a simplified
version of the Periodic
Table
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Atomic Number = no. of protons
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Number of protons = number of electrons
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Neutral overall charge
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Eg if the atomic number = 7 then number of
protons = 7 and the number of electrons = 7
If the atomic number = 3 then the number of
protons = 3 and the number of electrons = 3
Fill out Protons and Electrons in your table
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Mass Number = the total weight of the atom
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Mass Number = no. of protons + no. of neutrons
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To calculate the Mass Number - Make a whole
number from the Relative Atomic Mass found on
the periodic table.
Eg RAM = 22.9 therefore mass number = 23
Eg RAM = 35.45 therefore mass number = 35
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Fill out the Mass Numbers in your table
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To find the number of neutrons subtract the
atomic number from the mass number.
Eg Mass no. = 24, Atomic no. = 12 (24 - 12 =
12) therefore number of neutrons = 12
Eg mass no. = 20, Atomic no. = 10
(20 – 10 = 10) therefore number of neutrons = 10
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Fill out number of neutrons in your table
Symbols can now be written like
this showing more information
Mass
number
Atomic
number
H