Title:
The Atom
and
The Periodic Table
Date: 06/10/2020
Today’s 7 Key Terms
ATOMIC NUMBER
MASS NUMBER
PROTONS
NEUTRONS
ELECTRONS
CHARGE
MASS
Remember!
Title: The Atom & The PTE. Date: 06/10/2020
Close all your books. Look at the term below and think.
The Atom.
THINK: 1 minute alone.
3 Questions to help you think
1. What does the word atom mean to me?
2. Are all things made up of atoms?
3. Can you think of & write the names of some atoms?
Now: 1. Open your copies, pair up and
2. WRITE DOWN what you both discussed.
Feedback from you:
Objectives of todays lesson (4)
1.To give student’s an understanding of the
structure of the atom.
2.To ensure students are confident with the
terms nucleus, proton, neutron and electron.
3.To help students recognise and differentiate
between atomic and mass numbers.
4.To ensure students know how electrons are
arranged in different atoms using the atomic
structure (the Bohr Model).
Close all your books, copies and
hardbacks now.
Put all pens & pencils down.
Focus on me please!
THE ATOM
A bit of history to start!
The Atom
The word atom comes from the Greek word ‘Atomos’
which means uncuttable.
When atoms were discovered scientists thought them
to be like snooker balls – they could not be split into
anything simpler.
Definition of an Atom: The smallest part of an
element which still has the properties of that
element.
Chemists later discovered that atoms were in fact
made up of even smaller particles called sub-atomic
particles.
Inside The Atom
All atoms consist of 3 sub-atomic particles:
 Protons,
 Neutrons,
 Electrons.
Inside The Atom
All atoms consist of 3 sub-atomic particles:
 Protons,
 Neutrons,
 Electrons.
Here’s 2 diagrams:
Inside The Atom
The 3 particles are entirely
different from each other.
Here is a table to summarise their differences:
P
P
N
N
These particles are extremely small.
Electrons (the smallest) are so small that 2000 equal
the mass of 1 proton or neutron.
We therefore round off the electron mass to zero!
Inside The Atom
Here is a diagram showing this more clearly.
Objective 1
To ensure students are confident with the subatomic structure of the atom.
ANY QUESTIONS ?
A Quick Check of Your Learning
All 3 sub-atomic particles have different types
of electric charge.
Question 1: What is the charge on a proton?
Answer: Positive (+1).
Question 2: What is the charge on an electron?
Answer: Negative (-1).
Atomic and Mass Numbers
A1
Atoms
of different elements differ from each other
by the number of protons, neutrons and electrons
they have.
Each element in the periodic table has a number
above and a number below its chemical symbol.
The smaller number is the atomic number.
Definition: The number of protons in the nucleus of
the atoms of that element.
The number of protons in an atom always equals the
number of electrons. This is how atoms are neutral.
Positive charge equals out negative charge.
Counting The Pieces
C
12
C
6
14
6
Atomic Number (Z)= number of protons
# of protons determines kind of atom
Mass Number = A
C
12
6
Atomic Number = Z
Atomic Number = number of electrons in a neutral atom
Mass Number (A) = the number of protons + neutrons
(remember electrons have almost zero mass so the mass must be
made up of protons & neutrons)
ATOMIC
NUMBER
The Atomic Number of The Elements
A1
Atoms
of elements differ from each other due to
their number of protons, neutrons and electrons.
Example: Sodium will be different to Gold.
Each element in the periodic table has a number
above and below its chemical symbol.
The smaller number is the atomic number.
Definition of atomic number: The number of
neutrons in the nucleus of atoms of that element.
The number of protons in an atom always equals the
number of electrons. This is how atoms are neutral.
MASS
NUMBER
The Mass Number of The Elements
A1 mass number is always the bigger number.
The
ITS ALWAYS A WHOLE NUMBER!!
Definition of mass number: The total number of
protons and neutrons in an atom.
The number of protons in an atom always equals the
number of electrons. This is how atoms are neutral.
Positive charge equals out negative charge.
Atomic and Mass Numbers
A1
The larger number is the
mass number.
Definition: The total number of protons and neutrons
in the nucleus of the atoms of that element.
To calculate the number of neutrons we subtract the
atomic number from the mass number.
Example:
Atomic and Mass Numbers
A1
Another
Example:
The small number is the
atomic number.
The larger number is the
mass number.
Symbols of Elements
Contain the symbol of the element, the mass
number and the atomic number
# protons
+ # neutrons
mass number
# protons
Mass
number
Atomic
number
X
Symbols
• Find the
– number of protons = 9 +
– number of neutrons = 10
– number of electrons = 9
– Atomic number = 9
– Mass number = 19
19
9
F
Symbols
Find the
– number of protons = 35
– number of neutrons = 45
– number of electrons = 35
– Atomic number = 35
– Mass number = 80
http://www.chem.purdue.edu/gchelp/liquids/bromine.gif
80
35
Br
Symbols
Find the
– number of protons = 11
– number of neutrons = 12
– number of electrons = 11
– Atomic number = 11
– Mass number = 23
23
11
Na
Sodium atom
Symbols
Find the
– number of protons = 11
– number of neutrons = 12
– number of electrons = 10
– Atomic number = 11
– Mass number = 23
23
11
1+
Na
Sodium ion
Symbols
If an element has an atomic number of
23 and a mass number of 51 what is
the
– number of protons = 23
– number of neutrons = 28
– number of electrons = 23
– Complete symbol
51
23
V
Symbols
If an element has 60 protons and 84
neutrons what is the
– Atomic number = 60
= 144
– Mass number
– number of electrons = 60
– Complete symbol
144
60
Nd
Symbols
If a neutral atom of an element has 78
electrons and 117 neutrons what is the
– Atomic number = 78
– Mass number = 195
– number of protons = 78
– Complete symbol
195
78
Pt
Objective 2
To give students an understanding of mass
numbers and atomic numbers.
ANY QUESTIONS ?
A Quick Check of Your Learning
You will need to be able to work out both the
atomic and mass numbers.
Question 1: What is the atomic number?
Answer: Number of protons in an atom.
Question 2: What is the mass number?
Answer: Number of protons and neutrons in an atom.
ELECTRONIC
CONFIGURATION
How Electrons are arranged
As we said already, electrons whizz at great speed
around the nucleus in energy levels or shells.
These shells can hold electrons as follows:
Shell Number
How many electrons it can hold
1
2
2
8
3
8
A Danish Scientist, Neils Bohr, first put forward the idea of
electron shells containing electrons orbiting the nucleus.
The way electrons are organised is called electronic
configuration.
Let’s now go ahead and look at some examples…
How Electrons are arranged
Let’s get started:
Shell
Electrons in shell
1
2
2
8
3
2
BOHR - RUTHERFORD DIAGRAMS
• Putting all this together, we get B-R diagrams
• To draw them you must know the # of protons, neutrons, and
electrons (2,8,8,2 filling order)
• Draw protons (p+), (n0) in circle (i.e. “nucleus”)
• Draw electrons around in shells
He
2 p+
2 n0
Li
Li shorthand
3 p+
4 n0
3 p+
4 n0
Draw Be, B, Al and shorthand diagrams for O, Na
2e– 1e–
Be
B
Al
4 p+
5 n°
O
5 p+
6 n°
13 p+
14 n°
Na
8 p+ 2e– 6e–
8 n°
11 p+ 2e– 8e– 1e–
12 n°
Objective 3
To help students appreciate how electrons area
arranged using the Bohr model.
ANY QUESTIONS ?
Remember!
The Key points so far
• Atomic number = number of neutrons in the nucleus.
• Mass number = number of neutrons + protons in the
nucleus.
• Bohr Model: Shells fill like this; 1st 2, 2nd 8 and 3rd 8
electrons.
• An Element: A substance that cannot be split into simpler
substances by chemical means.
• A Mixture: consists of two or more different substances
mingled together but not chemically combined.
• A compound is a substance made up of two or more
different elements combined together chemically.
• A compound has different properties to the elements
from which it is made because the atoms are arranged
differently.
Learning Outcomes (3)
At the end of this lesson you should be able to:
State the names and properties of the subatomic
particles.
Recall and calculate the mass and atomic
numbers of different atoms.
Describe and model how electrons are arranged
within atoms using the Bohr model.
Elements, Mixtures,
Compounds.
Remember!
Title: Elements, mixtures and compounds.
Close all your books. Look at the term below and think.
The Atom.
THINK: 1 minute alone.
3 Questions to help you think
1. What are the (sub-atomic) particles within an atom?
2. Why do I know about these particles locations?
3. What are the properties of these particles?
Now: 1. Open your copies, pair up and
2. WRITE DOWN what you both discussed.
Feedback from you:
OBJECTIVES OF TODAY’S LESSON (6)
To give students a better understanding of atomic and
mass numbers of elements.
To help students appreciate how electrons area
arranged using the Bohr model.
To give students an appreciation of the layout of the
periodic table.
To ensure students can recognise the names of
elements and write their symbols.
To give students an understanding of mixtures.
To demonstrate to students that the properties of
compounds are different from their starting elements.
Close all your books, copies and
hardbacks now.
Put all pens & pencils down.
Focus on me please!
Inside The Atom
All atoms consist of 3 sub-atomic particles:
 Protons,
 Neutrons,
 Electrons.
A Quick Check of Your Learning
You will need to be able to work out both the
atomic and mass numbers.
Question 1: What is the atomic number?
Answer: Number of protons in an atom.
Question 2: What is the mass number?
Answer: Number of protons and neutrons in an atom.
Atomic and Mass Numbers of The Elements
Now let’s try a few
questions
Atomic and Mass Numbers of The Elements
Element
Lithium
Cobalt
Sulphur
Mass Number
(protons +
neutrons)
Atomic
Number
(protons)
No. of
neutrons
A Quick Check of Your Learning
Try these questions now
NONMETALS
METALS
Objective 3
To give students an appreciation of the layout of the
periodic table.
ANY QUESTIONS ?
A Quick Check of Your Learning
The Periodic Table gives us a huge amount of
information about Chemistry and the world
around us.
Question 1: Who can summarise how is the
periodic table is arranged?
Answer: According to metals and non-metals.
The Elements
Everything in the known universe (all
matter) is made from elements.
An element is a pure substance.
The Elements
An element is made up of only one type of atom
(copper wire contains only copper atoms).
They are the simplest substances that exist.
Definition: An element is a substance that cannot
be split up into simpler substances by chemical
means.
The properties of each element is different.
Each element is unique!
The Elements – Appearance
Nitrogen
Mercury
Aluminium
Gold
Names and Symbols of The Elements
All the elements we know have different names.
These are written in a particular way by scientists.
For example:
• All elements have symbols to identify them
• All symbols are either one or two letters
• First letter is a capital, the second is always small.
Example: Hydrogen. Its symbol is H.
Helium. Its symbol is He.
Title: Elements,
TheCompounds
Elementsand Mixtures
Task: Listen & watch carefully to write down as
many elements as you can.
1 bar of chocolate each for more than 40 + symbols!
The Elements - Symbols
Task: Working in pairs, fill in
this table using your periodic
table.
Extension question:
Discuss and record how many
elements there are on the
entire periodic table?
Element
Hydrogen
Helium
Oxygen
Symbol
C
Au
Sodium
Sn
Mercury
Aluminium
Fe
Silicon
Sulfur
Objective 4
To ensure students can recognise the names of
elements and write their symbols.
ANY QUESTIONS ?
A Quick Check of Your Learning
The Periodic Table of the Elements is easy to
read with a bit of practice.
Question 1: But what is the definition of an
element in chemistry?
Answer: An element is a substance that cannot
be split up into simpler substances by chemical
means.
Mixtures
We have learned about the elements so far.
So, what are mixtures then? Think-Pair-Share.
Definition: A mixture consists of two or more different
substances mingled together but not chemically combined.
Examples:
Air (different gases)
Earth (stones, sand + minerals)
Objective 5
To give students an understanding of mixtures.
ANY QUESTIONS ?
A Quick Check of Your Learning
We buy, use and eat mixtures everyday.
Question 1: But what is the definition of a
mixture?
Answer: A mixture consists of two or more
different substances mingled together but not
chemically combined.
Example: sugar and water,
salt and water,
iron and sulphur.
Compounds
If you look at the Periodic Table you wont find salt, sugar or
water. Why? Because they are not elements.
Salt, sugar and water are compounds.
So, what is a compound?... Discuss in group’s of three’s.
Definition: A compound is a substance made up
of two or more different elements combined
together chemically.
Examples:
Properties of Elements and Compounds
Chlorine gas
Deadly weapon in WW2
Sodium metal
+
Salt – We would die
without it
Properties of Elements and Compounds
Hydrogen gas-Highly explosive Oxygen gas-Burns things
+
Water
Puts out fires!
Compounds
Properties of compounds are usually different
from its starting elements.
Example: Reaction of Iron (…) + Sulfur (…)
Write down everything that you observe happened.
The reaction between Iron and Sulphur
1. Compare the particles of the elements, mixture & the compound.
2. Why does iron sulphide have different properties to the elements
it is made of?
A compound has different properties to the elements
from which it is made because the atoms are joined
differently.
STUCK? LET’S HAVE INTERACTIVE ZOOM
IN
Objective 6
To demonstrate to students that the properties of
compounds are different from their starting
elements.
ANY QUESTIONS ?
A Quick Check of Your Learning
We are made up of chemical compounds and
they surround us everywhere we look.
Question 1: But what is the definition of a
compound?
Answer: A compound is a substance made up of
two or more different elements combined together
chemically.
Example: Water – Hydrogen & Oxygen
Salt – Sodium & Chlorine
Task
Think (10 seconds) – pair (30 seconds) - share
about what these diagrams show.
Write down in your copy what each set
shows.
Element
Compound
Mixture
C
A
B
What do you think A, B and C are?
Elements and Compounds
1. The following is a random list of four elements and four
compounds.
2. Textbooks closed: Think about and discuss the definitions
of an element and a compound (15-20 seconds).
3. Scan the list and decide which are to be listed as
elements or compounds on your worksheet.
Carbon dioxide Sulfur Glucose Sodium Salt Oxygen
Silicon Iron sulfide.
Element
Compound
To recap your learning so
far we will do a short
true/false table quiz.
Green pens at the ready!!
Remember!
1. Iron contains only one type of atom.
TRUE/FALSE QUIZ
2. All elements are solids.
3. An apple is an element.
4. Water is an element: it is made up of water and Oxygen atoms.
5. All gases are elements.
6. Iron Sulfide is a compound.
7. The symbol for Sodium is So.
8. Compounds always contain different types of atoms.
9. Lead atoms are heavier than Helium atoms.
10.There are about 1000 different elements in existence.
The 7 Key points of todays lesson
• Atomic number = number of neutrons in the nucleus.
• Mass number = number of neutrons + protons in the
nucleus.
• Bohr Model: Shells fill like this; 1st 2, 2nd 8 and 3rd 8
electons.
• An Element: A substance that cannot be split into simpler
substances by chemical means.
• A Mixture: consists of two or more different substances
mingled together but not chemically combined.
• A compound is a substance made up of two or more
different elements combined together chemically.
• A compound has different properties to the elements
from which it is made because the atoms are arranged
differently.
Today’s 8 Key Terms
ATOMIC NUMBER
MASS NUMBER
ELECTRONIC CONFIGURATION
PROTONS
NEUTRONS
ELEMENT
MIXTURE
COMPOUND
Written Homework and Study Work for Tuesday 28th
Written Homework:
Blue Workbook Chapter 20 page 88 – 89
Questions 1 - 9.
Study Work:
Revise chapter 21 for short test on Friday
of week we return from mid term break.
Learning Outcomes (5)
At the end of this lesson you should be able to:
Recall and calculate the mass and atomic
numbers of different atoms.
Describe and model how electrons are
arranged within atoms using the Bohr model.
Describe the layout of the periodic table.
Recall some examples of the names of
elements and their corresponding symbols.
Observe the reaction of two elements forming
a compound and compare properties before
and after the reaction the reaction has taken
place.
To recap your learning so
far on breathing we will do
a few worksheet questions.
Green Pens at the ready!!