1. Periodic Table of Elements -1
Keywords
Periodic table الجدول الدوري
Symbol الرمز
Group المجموعة
Period الدورة Atomic number العدد الذري
Mass number العدد الكتلي

3. helium carbon nitrogen sodium silver oxygen mercury neodymium chlorine
gold
mercury
oxygen
hydrogen
helium
sodium
niobium
neodymium
carbon

4. Elements Everything is made up of elements.
Scientists have identified 90 naturally occurring elements
Scientists also created about 28 others.

5. Elements
The elements, alone or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe.

6. Periodic Table
The periodic table organizes the elements in a particular way.
The periodic table helps you to predict the properties of an element and how it can react.

7. Atomic Number
This refers to how many protons an atom of that element has.
No two elements, have the same number of protons.

8. Atomic number & Mass number
On the periodic table we find elemental symbols like this:
The largest number is called the “mass number”
This number tells us the mass of an atom of this element.
Q. Where does almost all the mass of the atom come from?
The nucleus!
Q. What particles were in the nucleus?
Protons & Neutrons!
Q. So what does the mass number also tells us?
The sum of (protons + neutrons)
Mass number 4 He 2
There are two numbers, one above the other below:

9. He Mass number 4 2 + - Proton Nucleus Neutron
2 protons + 2 neutrons = mass number of 4
So why is Helium’s mass number = 4?
2 x
Proton + - 4 He 2
Nucleus
2 x
Neutron

10. Mass Number The nucleus contains protons and neutrons.
When you add up the numbers of protons and neutrons you get the mass of the atom!
This is called the “Mass number”

11. Atomic Number
Protons
The atomic number tells us the number of ______________
Which is the same as the number of _________ + -
Electrons
Atoms have an equal number of positive protons and negative electrons. This is so the atom has no overall electrical charge. 4 He 2
Atomic Number

12. Look at the periodic table, what do you notice about the numbers?

13. H He Li Be Key fact! The number of protons defines the element!1 H 4 He 2 7 Li 3 9 Be 4
The number of protons defines the element!
Elements are arranged on the periodic table in order of their atomic numbers.
If you change the number of protons (atomic number) you change the element!

14. He 4 2 Mass number Protons + Neutrons
So how do we work out the number of neutrons?
Mass number – atomic number = number of neutrons.
4 – 2 = 2 neutrons.
Atomic number Protons
Atomic number

15. Practice: Protons, Neutrons and Electrons
Key maths skill 4 He 2 2 7 Li 3 3 31 P 15 15
Protons ______
Neutrons _____
Electrons _____
Protons ______
Neutrons _____
Electrons _____
Protons ______
Neutrons _____
Electrons _____ 2 4 16 2 3 15 23 Na 11 11 20 Ne 10 10 80 Br 35 35
Protons ______
Neutrons _____
Electrons _____
Protons ______
Neutrons _____
Electrons _____
Protons ______
Neutrons _____
Electrons _____ 12 10 45 11 10 35

16. Periodic Table of Elements – Lesson 2
Keywords
Periodic table الجدول الدوري
Symbol الرمز
Group المجموعة
Period الدورة
Atomic number العدد الذري
Mass number العدد الكتلي

18. Groups Columns of elements are called groups .
have the same number of electrons on the outer shell
Each horizontal row of elements is called a period.
Elements that have the same number of shells.

19. Groups

31. Questions
1- Explain the difference between a Group and a Period
2-Elements

32. Alkali Metals
Group 1 elements are also known as Alkali metals (You don’t need to remember that)
Alkali metals are in group 1, which means that they have only 1 electron on the outer shell

33. Group 2 Earth Metals They have two electrons on the outer shell.
Alkaline earth metals include magnesium and calcium, among others.

34. Group 7 - Halogens Group 7 elements are also called Halogens.
How many electrons do they have on the outer shell?

35. Group 8- Noble Gases
Elements in this group have a FULL outer shell.

36. TASK! Find the following elements Group 1 Period 2 _____________