1. Atoms and elements

2. ATOM ELEMENT COMPOUND MIXTURE Match up:
……………………………………………………………………………………………………………………………
ATOM
Two or more elements that are chemically bonded together
ELEMENT
A tiny particle that all substances are made of.
COMPOUND
A substance that is made of one sort of atom.
MIXTURE
Different substances that are not chemically joined but they are…

3. Atoms All substances are made of atoms.
An element is made up of one atom.
There are around 100 different elements which are shown in the periodic table.

4. Atomic Structure Sub-atomic particles Nucleus Electrons Neutrons
Protons

5. Atomic Structure
The atom has a nucleus which is made up of sub atomic particles that include protons and neutrons. Electrons surround the nucleus, these are even smaller subatomic particles.
proton
electron
neutron +
electron - -
proton +
neutron
Protons have a relative charge of +1, neutrons are neutral/ relative charge of 0 and electrons have a relative charge of -1. The number of electrons in an atom is equal to the number of protons in its nucleus. This means atoms have no overall electrical charge.

6. Non- METALS
Groups (columns)
METALS
Periods (rows)

7. Mg Chemical Symbols First letter: CAPITAL Second letter: lower case 12
Magnesium

8. Mass number and atomic number
Atomic number: Number of protons it contains.
Mass number: Number of protons and neutrons it contains.
Mass number
The number of protons and electrons in an atom are equal.
To work out the number of neutrons in an atom, you take away the atomic number from the mass number. 24 Mg 12
Atomic number

9. Mass number and atomic number35
Mass number:
Atomic number:
Number of protons:
Number of neutrons:
Number of electrons: 35 Cl 17 17
35-17= 18 17 17
Chlorine

10. Electronic Structure Protons: Neutrons: Electrons: Boron Atom 5 6 5
In the following slides,
The nucleus is represented as:
Each energy level is shown as:
Each electron is shown as:
Shell

11. Drawing Electronic Structures
DON’T PANIC! All will be explained shortly!
Find the element in the period table
Work out the period it is in and draw that number of circles (shells) around the nucleus.
Work out which group the element is in and draw that number of electrons in the outer circle/shell (8 electrons for group 0 elements except helium which has 2 electrons)
Fill in the other circles with as many electrons as required.

12. Draw the electronic structure of the element Fluorine.
Example
Draw the electronic structure of the element Fluorine.

13. Draw the electronic structure of the element Fluorine.
Example
Draw the electronic structure of the element Fluorine. 1 2

14. Draw the electronic structure of the element Fluorine.
Example
Draw the electronic structure of the element Fluorine.
It is in the 2nd period, so I draw 2 shells around the nucleus of my diagram.

15. Draw the electronic structure of the element Fluorine.
Example
Draw the electronic structure of the element Fluorine.

16. Draw the electronic structure of the element Fluorine.
Example
Draw the electronic structure of the element Fluorine.
It is in the 7nd group, so I draw 7 electrons in the outer shell.

17. Max number of electrons
Example
Draw the electronic structure of the element Fluorine.
Each electron in an atom is found in a particular energy level. Each energy level can only hold up to a certain number of electrons before it becomes full. Here are the maximum number of energy levels each shell can hold:
Energy level/ shell
Max number of electrons
First 2
Second 8
Third

18. Max number of electrons
Example
Draw the electronic structure of the element Fluorine.
Energy level/ shell
Max number of electrons
First 2
Second 8
Third
I add 2 electrons to the first shell. I do not need to fill the second shell because I have already done it.

19. Draw the electronic structure of the element Fluorine.
Example
Draw the electronic structure of the element Fluorine. F
The amount of electrons in my diagram and the atomic number of fluorine are the same, therefore I know that I have completed this diagram correctly. 9
fluorine