All notes on the atomic structure and the periodic table. Very easy to understand and fill with simple explanations

1. 3D MOTIVATION FOR CLASS:

2. Basic Structure of the Atom

3. Description of the Bohr Diagram
Bohr diagram of potassium for example:
Bohr’s model consists of a small nucleus (positively charged)
surrounded by negative electrons moving around the nucleus
in shells or energy levels. Bohr found that an electron located
away from the nucleus has more energy, and the electron
which is closer to nucleus has less energy.
This is an example of the Bohr diagram for potassium.
The Bohr model of the atom was proposed by Neil Bohr in
1915.

4. Bohr Diagram of the Calcium Atom
This is the diagram of
the Bohr atom for
calcium, however the
calcium atom used
here is just to show
you an example of
how all atoms will
look. Hence all atoms
will have different
number of protons,
neutrons and
electrons.

5. Two main parts of the Atom
► 1. Nucleus
► 2. Electron shells or energy levels and it is sometimes referred to as the electron
cloud.

6. The Nucleus
► The nucleus is found at the center of the
atom and contains subatomic particles
that are called protons and neutrons.
Protons carry a positive charge, whereas
neutrons carry no charge. The protons
and neutrons are held together in the
nucleus by the nuclear strong force,
which overcomes the repulsion between
positively charged protons.

7. The Energy Levels,
shells or electron cloud
The electron clouds are also known as electron
shells, and they're also known as energy levels.
Energy
levels or
shells

8. The three
subatomic
Particles in an
atom:

9. PRESENTATION
TITLE

10. PRESENTATION TITLE

12. Electrons
10/20/2022 PRESENTATION TITLE 12
Location
Electrons are located in the shells or energy levels in
an atom.
Electrons ORBIT THE NUCLEUS
Relative Mass
Electrons are so small that they are often described as
having no mass, however the relative mass of
electrons is : 1/1840
Charge
Electrons have a NEGATIVE CHARGE
ELECTRONS

13. Properties of the three Subatomic Particles

14. A ROW IS A PERIOD
A Column is a group
•THE PERIODIC TABLE
•WHAT IS THE PERIODIC TABLE?
•THERE ARE MORE THAN 100 DIFFERENT ELEMENTS. THE PERIODIC TABLE IS A
TABLE WHICH CONTAINS ALL THE ELEMENTS ARRANGED IN ORDER OF
INCREASING ATOMIC NUMBER. THE VERTICAL COLUMNS IN THE PERIODIC
TABLE ARE CALLED GROUPS. EACH GROUP CONTAINS ELEMENTS THAT HAVE
SIMILAR PROPERTIES.

15. THE PERIODIC TABLE

16. Since the periodic table has elements let us
define an element:
An element is a pure substance that cannot be broken down into any
simpler substance by ordinary chemical or physical means. The
smallest particle in an element which has the same properties of as
the element is an atom.

17. For example:
Gold cannot be broken down into a simpler
substance. The gold will always contain only
gold atoms.

18. The Relationship between atoms and
Elements
An element is made up of one type of atom
The chemical properties of an element depend on the
arrangement of electrons in an atom.
The number of protons in an atom determines an
element’s physical properties.
Atoms have the same chemical makeup, size and mass as
their respective element.

20. When you zoom in on each box in your
periodic table you will see that there is a
symbol along with two numbers; one above
the symbol and one below.

21. What do these represent though, you may
ask

22. It’s Simple the symbol represents the element: its
just a shortening for the element and we have the
mass number and the atomic number.

23. ATOMIC AND MASS NUMBER OF ELEMENTS
►Atomic number
►Atomic number = the number of protons in the nucleus of an atom
►The atomic number = the number of electrons in an atom.
►Eg: Atom of oxygen with atomic number 8
►Number of electrons=8
►Number of protons= 8
►MASS NUMBER
•THE NUMBER OF PROTONS PLUS THE NUMBER NEUTRONS IS A KNOWN AS THE MASS NUMBER, WITH
SYMBOL A. (THE NUMBER OF NEUTRONS CAN BE CALCULATED BY SUBTRACTING THE ATOMIC
NUMBER FROM THE MASS NUMBER THAT IS A- Z. )

24. Finding the number of neutrons
Mass number = 4
Atomic number = 2
Number of neutrons= Mass
number – Atomic number
= 4-2= 2
The mass number is always the larger
number!

25. What is the mass
number?

26. Maximum number of electrons each shell
can hold Formula
►Calculate for shells 2,3 and for and click the next slide to see if you got them
correct

27. Maximum number of Electrons each shell can
hold:
Electron Shell number (n) Max number of electrons (2n2
)
1 2
2 8
3 18 (8 then 10)
4 32

28. Atomic Structure of the first twenty elements:

29. What is Electronic Configuration?

30. Rules for determining Electronic
configuration:
►If we know the number of electrons in an atom, we can work out the electronic configuration because
the electrons in an atom fill the shells according to the following rules:
1) Electrons fill up the shells in order, beginning with the lowest energy level.

31. Rules for determining Electronic
configuration:
2) ELECTRONS GENERALLY FILL ONE SHELL BEFORE ENTERING THE NEXT SHELL
(HOWEVER THERE IS ONE EXCEPTION AND THAT IS REGARDING SHELL NUMBER 3)
•THERE IS SOMETHING UNUSUAL THAT OCCURS IN SHELL NUMBER 3. WHEN 8
ELECTRONS HAVE BEEN PLACED IN SHELL NUMBER 3, THE NEXT 2 ELECTRONS
ARE PLACED IN SHELL NUMBER 4. ONLY AFTER THESE TWO ELECTRONS HAVE
BEEN PLACED IN SHELL NUMBER 4 ARE THE REMAINING 10 ELECTRONS PLACED
IN SHELL NUMBER 3.

32. Rules for determining Electronic
configuration:
3) Each shell can hold the maximum number of electrons as shown in the table previously given.

33. Rules for determining Electronic
configuration:
4) WE CAN WRITE THE ELECTRONIC CONFIGURATION BY FIRST WRITING THE SYMBOL OF THE ELEMENT,
FOLLOWED BY THE NUMBER OF ELECTRONS IN EACH SHELL SEPARATED BY COMMAS.

34. Rules for determining Electronic
configuration:
FOR EXAMPLE:
POTASSIUM K, HAS 19 ELECTRONS SO WHEN WE PLACE THE FIRST 2 ELECTRONS ON THE FIRST
SHELL, WE HAVE 17 ELECTRONS REMAINING, AFTER PLACING 8 ON THE SECOND SHELL WE
WILL HAVE 9 ELECTRONS REMAINING. FINALLY, WE WILL NOW HAVE 9 ELECTRONS AND WE
KNOW 8 WILL GO ON THE THIRD SHELL AND 1 ON THE FOURTH SHELL (SIMPLY BECAUSE
SHELL 3 IS DIFFERENT FROM THE OTHERS)
•SO, WE WILL WRITE THIS AS: K (2, 8, 8, 1)
•K IS THE CHEMICAL SYMBOL FOR POTASSIUM

35. Representing the Electronic configuration of
atoms by drawing shell diagrams steps
► Representing the Electronic configuration of atoms by drawing shell diagrams steps
► 1) Determine the number of protons, neutrons and electrons in the atom using the atomic
and mass number.
► 2) Draw a small circle for the nucleus and write the number of protons and neutrons
inside the circle.

36. Representing the Electronic configuration of
atoms by drawing shell diagrams steps
•3)WORK OUT THE ELECTRONIC CONFIGURATION BY FILLING UP THE SHELLS
WITH ELECTRONS IN ORDER
•FILL UP THE FIRST SHELL AND THEN WHEN THAT IS FULL START TO FULL
SHELL 2 AND SO ON.
•4)REPRESENT THE ELECTRONIC CONFIGURATION BY DRAWING CONCENTRIC
CIRCLES AROUND THE NUCLEUS. THE NUMBER OF CIRCLES YOU DRAW IS
DETERMINED BY THE NUMBER OF SHELLS THAT YOU ARE GOING TO FILL OR
PARTIALLY FILL. DRAW THE 2 ELECTRONS IN SHELL NUMBER 1 AS A PAIR.
DRAW THE ELECTRONS IN THE OTHER SHELLS AS PAIRS WHEN THE SHELL
CONTAINS 5 OR MORE ELECTRONS.