TOPIC : PERIODICITY IN PROPERTIES

CHEMISTRYCLASSIFICATION OF ELEMENTSAND PERIODICITY PROPERTIES

TEACHER: Mrs. V. GOWRI (PGT-Chemistry)

BYVISHNU PRASAD VP

XI A 1

KENDRIYA VIDYALAYA

Periodic Properties

Atomic Size And RadiiIonization energyElectron Gain EnthalpyElectro negativityMetallic characterNon Metallic Character

Periodic Properties

Group Period Exception

Atomic Size / Radii Al to Ga Halogen to Noble

Gases

Ionization Energy Nitrogen-Oxygenpair

Electron Gain Enthalpy

Chlorine –Fluorine pair

Electro negativity--------

Metallic character --------

Non metallic Character

--------

An Outlook of Trends of Periodic Properties in Groups And Periods

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.

Atomic Size

3 4 5 6 7 8 90

20

40

60

80

100

120

140

160

Atomic Radius vs Atomic Number

Atomic Radius vs Atomic Number

Atomic Size

Series10

50

100

150

200

250

300

350

400

Group 1 (li to Cs)Group 17 (F to I)

Atomic Size

Covalent RadiiMetallic RadiiVanderwaal’s RadiiIonic Radii

CationAnion

Atomic Radius

Anion > Atom > CationZ+ > Z > Z-

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.

Ionization Energy

Ionization Energy

The energy released when an electron is injected into an isolated gaseous atom

Cl + e- Cl- + EnergyExceptional:

F has more EGE than Cl ( in spite of decrease along the group),due toFluorine is small in sizeLone pair – Lone pair attraction is more.

Electron Gain Enthalpy

Se-ries1

-100

-50

0

50

100

150

Chart Title

Group 1Group 0

Axis Title

Electron Gain Enthalpy

The power of an atom to pull the mutually shared pair of electron towards itself. negative elements

Most electronegative element is Fluorine(4)Scales:

MillikanPauling

Example: HF : H---FH~ + --- F~ - -partial charge

Electro Negativity

Metallic CharacterIncreases along the group.Decreases along the period.

Non character Decreases along the group.Increases along the period.

Metallic And Non- metallic character

An outlook of periodic periodic properties