“This law states that the physical and chemical properties of elements are arranged in increasing order of their atomic numbers in periodic function.”The modern periodic law is a statement that describes the patterns observed in the physical and chemical properties of elements when they are arranged in order of increasing atomic number. It states that "the physical and chemical properties of elements are periodic functions of their atomic number." This law is based on the fundamental concept that the behavior and properties of atoms are determined by the number of protons in their nucleus, which is also known as the atomic number. As the atomic number increases, so does the number of electrons in the atom, and this increase in electrons leads to the formation of new energy levels and sub-levels within the atom. The modern periodic law states that these new energy levels and sub-levels lead to similar chemical and physical properties being repeated at regular intervals, or periods, throughout the periodic table. For example, elements in the same group, or column, of the periodic table tend to have similar chemical properties because they have the same number of valence electrons, which are the electrons in the outermost energy level. In summary, the modern periodic law is a statement that describes the recurring patterns of chemical and physical properties of elements based on their atomic number. It provides a framework for understanding the behavior and properties of the elements and serves as a fundamental principle in the study of chemistry.The modern periodic law is an extension of the earlier periodic law proposed by Dmitri Mendeleev in 1869, which arranged the elements in order of increasing atomic weight and observed similar chemical and physical properties at regular intervals. However, with the discovery of isotopes and the development of more precise methods for measuring atomic mass, it became clear that the order of elements based on atomic weight was not always consistent with their chemical and physical properties. The modern periodic law, which was proposed by Henry Moseley in 1913, overcame this limitation by using atomic number as the basis for arranging the elements. Atomic number is the number of protons in an atom's nucleus, and it uniquely identifies each element. By arranging the elements in order of increasing atomic number, Moseley discovered a much more consistent pattern of chemical and physical properties than Mendeleev had observed. The periodic table is arranged in rows, called periods, and columns, called groups. Each period corresponds to a new energy level being filled with electrons, while each group corresponds to elements with similar properties due to having the same number of valence electrons. The properties of elements within a group tend to be more similar to each other than to elements in other groups. For example, the alkali metals (Group 1) are all highly reactive metals that readily lose their oute

1. Review of the previous lesson
Presentation of the lesson

2. MODERN PERIODIC LAW

3. LEARNING OBJECTIVES
Explain the periodic law.
Arrange the given element in the periodic table.
Recognize the importance of arranging an
element according to increasing atomic number.

4. GAME: PERIODIC PEOPLE
• Your mission is to arrange the pictures to the blank table.
• Procedure
1. Arrange them in one single line so that each little man is
different from every other by a particular number.
2.Arrange them going up and down and across from left to right
3. Look for the pattern including the body size (thin to fat), the
number of antenna(1 to 8), the number of arms(1 to 3), the
number of fingers (1 to 18), the facial expression (sad to happy)
4. The body marking should be the same every column

6. •Why is it important to
arrange the elements?
•How are elements in the
modern periodic table
arranged?

7. Periodic Table
Dmitri Mendeleev
 first arranged the periodic table
 he arranged them by atomic mass
 he noticed that they had similar
chemical and physical properties
but some elements were out of
order

8. Henry Moseley
Arranged the elements by
atomic number
modern table is arranged this
way

9. Periodic Law states that “When elements
are arranged in order of increasing atomic
number, there is a periodic repetition of
their physical and chemical properties.

10. Classification of elements in the Periodic
Table
• Representative elements- column 1,2,13-17
• Noble gas- column 18
• Transition metal- column 3-12
• Inner transition metals- bottom of the periodic table the actinides
and the lanthanides group

12. Types of Elements on the
Periodic Table
•Metals
•Non-metals
•Metalloids

13. METALS
left side of the periodic table
Luster
ductile
malleable
good conductors of heat and electricity
high melting and boiling pt.

14. NONMETALS
the right on the periodic table
 dull
brittle solids
poor conductors of heat and electricity
low melting and boiling pt.

15. Metals

16. Metalloids are located at the boundary of the metals
and non-metals
Semi-metals - Has properties of both metals and
nonmetals
Staircase
Boron, silicon, germanium, arsenic, antimony,
tellurium, and polonium.
METALLOIDS

18.  7 horizontal
rows of
elements
 members have
the same # of
principal
energy levels
Periods
GROUPS OR FAMILIES
 18 vertical
columns of
elements
 members have the
same number of
valance electrons
 members of the
group have similar
chemical
properties

19. GROUP
P
E
R
I
O
D

20. THERE ARE 8 GROUPS OF
ELEMENTS WHICH ARE
ALSO CALLED FAMILIES

21. Group 1A - Alkali Metals
valence electron(s) 1
most active metals
not found in nature by themselves
form stable compounds

22. Group 2 - Alkaline Earth Metals
 valence electrons 2
 second most active metal
 some are not found in nature by themselves

23. Group 3A – Boron Group
 valence electrons 3
 The elements are not all solid metals
 Contains metal and metalloids elements

24. Group 4A – Carbon Group
 valence electrons 4
 Relatively unreactive
 Contains metal, nonmetals, and metalloids elements

25. Group 5A – Nitrogen Group
 valence electrons 5
 contains metal, nonmetals, and metalloids
elements

26. Group 6A – Oxygen Group
 valence electrons 6
 Contains metal, nonmetals, and
metalloids elements

27. Group 7A - Halogens
 valence electrons 7
 most common ion -1
 have all states of matter at room temp.
 F2, Cl2 gases
 Br2, liquid
 I2, solids
 are the most reactive non metals

28. Group 8A/0 - Noble Gases
 valence electrons 8
 Inert gases (non reactive)
 have the most stable electron configuration-
8 e in the valence shell
 Kr and Xe can react with fluorine-they have
an oxidation number other than 0

31. ½ sheet of paper
Is it easy to arrange the elements
based on increasing atomic
number? Why?
How will you relate this in your
life as student?

33. Assessment
Draw a blank periodic table , place the following
elements with their respective atomic number.
1. Na-11 6.Be-4 11. C-6
2. Ca-20 7. Pd-46 12. Au-79
3. Cl-17 8.He-2 13. Kr-36
4. Fe-26 9. S -16 14. I-53
5. Hf-72 10. Al-13 15.Pb-82

34. Thank you