This document discusses periodic trends in atomic properties such as atomic size, ionization energy, electron gain enthalpy, and electronegativity. It notes that atomic size increases down groups and decreases left to right across periods, with some exceptions. Ionization energy generally increases across periods but nitrogen is an exception having a higher value than oxygen. Electron gain enthalpy decreases down groups with the exception of fluorine having a higher value than chlorine. Metallic character increases down groups and decreases across periods, while nonmetallic character shows the opposite trends.

1. TOPIC : PERIODICITY IN PROPERTIES
TEACHER: Mrs. V. GOWRI (PGT-Chemistry)
BY
VISHNU PRASAD VP
XI A 1
KENDRIYA VIDYALAYA

2.  Atomic Size And Radii
 Ionization energy
 Electron Gain Enthalpy
 Electro negativity
 Metallic character
 Non Metallic Character

3. Periodic Properties
Group
Period
Exception
Atomic Size / Radii
Al to Ga
Halogen to Noble Gases
Ionization Energy
Nitrogen-Oxygen
pair
Electron Gain Enthalpy
Chlorine –Fluorine
pair
Electro negativity
--------
Metallic character
--------
Non metallic Character
--------

4.  In group, size increases from top to bottom due to
formation of new shells
 In period ,size decreases from left to right due to
effective nuclear charge
 Exceptional:
 In period, Halogens are slightly smaller than noble
gases. (since noble gas have completed octet)
 Atomic size doesn't increase much when we move from
Al to Ga due to poor shielding of inner core electrons.

5. Atomic Radius vs Atomic Number
160
140
120
100
80
Atomic Radius vs
Atomic Number
60
40
20
0
3
4
5
6
7
8
9

6. 400
350
300
250
200
Group 1 (li to Cs)
150
Group 17 (F to I)
100
50
0

7.  Covalent Radii
 Metallic Radii
 Vanderwaal’s Radii
 Ionic Radii
 Cation
 Anion

8.  Energy required to remove an electron from an
isolated gaseous atom

Na
Na + + e Exceptional:
 Nitrogen – Oxygen : Though I.E., increases along the
period, nitrogen has more I.E., than Oxygen .Because
nitrogen is already half filled & more stable.

10.  The energy released when an electron is injected into
an isolated gaseous atom

Cl + eCl- + Energy
 Exceptional:
 F has more EGE than Cl ( in spite of decrease along the
group),due to
 Fluorine is small in size
 Lone pair – Lone pair attraction is more.

11. Chart Title
150
Axis Title
100
50
0
-50
-100
Group 1
Group 0

12.  The power of an atom to pull the mutually shared pair
of electron towards itself. negative elements
 Most electronegative element is Fluorine(4)
 Scales:
 Millikan
 Pauling
 Example: HF : H---F
 H~ + --- F~ - -partial charge

13.  Metallic Character
 Increases along the group.
 Decreases along the period.
 Non character
 Decreases along the group.
 Increases along the period.