(i) Periodic properties and their variations in groups and periods. (ii) Periodicity on the basis of atomic number for elements. 1.atomic size 2. ionisation POTENTIAL/ 3,electron affinity 4. metals non metals 5. density Periodic Trends Periods groups Mendeleev periodic table Moseley periodic table long form of periodic table

1. The periodic table
also known as the periodic table of
elements,
is a tabular display of the chemical
elements,
which are arranged by
atomic number,
electron configuration, and
recurring chemical properties.

4. Period –In The Modern Periodic
Table
A period is a horizontal row of the periodic table.
There are seven periods in the periodic table, with each
one beginning at the far left.
A new period begins when a new principal energy level
begins filling with electrons.

5. Period 1 has only two elements (hydrogen and helium),
while periods 2 and 3 have 8 elements.
Periods 4 and 5 have 18 elements.
Periods 6 and 7 have 32 elements because the two bottom
rows that are separated from the rest of the table belong to
those periods.
They are pulled out in order to make the table itself fit more
easily onto a single page.

7. Property Trends Of Elements-
From left to right
Number of Electrons Shells : Remain Same
Valence Electrons : Increases By One
Non –Metallic Character : Increases

8. Groups In The Modern Periodic Table
A group is a vertical column of the periodic table, based on
the organization of the outer shell electrons.
There are a total of 18 groups.

10. Property Trends Of Elements –On
moving Down a Subgroup
Valence Electrons : Remains Same
Chemical Properties : Remains Similar
Metallic Character : Increases

11. Periodic Properties of Elements

12. Periodicity In Properties
Repetition of properties after a certain interval is
called periodicity of properties.
If elements are arranged in increasing order of
their atomic number in the periodic table,
then elements repeat its properties after a definite
interval.
This repetition of properties is known
as periodicity of properties.

13. Atomic Radius
•Atomic radius
• is the distance
•from the centre of the nucleus
•to the outermost shell containing electrons.

14. • Factors Affecting Atomic Size:
• Number of Shells: Atomic size increases with the increase in the
number of electronic shells. ...
• Nuclear Charge: As the nuclear charge increases the atomic radius
decreases due to increase in the attractive force on the outermost
electrons.

19. Factors affecting Ionization Potential
•Atomic Radius-
Increases in atomic radius decrease in I.P
Nuclear Charge-
Increase in Nuclear Charge Increase In
I.P

21. Electron Affinity
•The electron affinity of an atom or
molecule is defined as the amount of
energy released when an electron is
added to a neutral atom or molecule ...

22. Factors Affecting E.A
Atomic Radius-
Increases in atomic radius decrease in I.P
Nuclear Charge-
Increase in Nuclear Charge Increase In I.P

23. •Electronegativity
is a measure of the tendency
of an atom to attract
a bonding pair of electrons
when in a compound

25. The metallic character
of an element
can be defined
as how readily an atom can lose an electron.
From right to left across a period,
metallic character increases
because the attraction
between valence electron and the nucleus
is weaker,
enabling an easier loss of electrons

26. •Non-metallic character –
relates to the tendency to accept electrons
during chemical reactions.
•Non-metallic tendency –
increases going from left to right
across the periodic table.