3 Periodicity
3 Periodicity
3 Periodicity
3 P E R l O D I C l T Y
Li Na K 7 39
2
23
7 23 29
Every
8 element has properties similar to the first element just like musical notes
Li Be B C N O F Na
Physical Chemical Properties of elements are periodic functions of their atomic numbers
electronic configurations
18 groups
7 periods
Elements with similarities in properties in the same group as they have same valence e
fall
Classification of
elements in Modern Periodic Table
placeddiagonally
b
Group 2 Alkaline earthmetals oxidesformedin Earth'scrust ni ns2np
P Block
np
Group 15 Pnictogens n5np3 havechalking properties don'tsupport combustion
Group 3 to Group 12
General config ns Cn 1 d
f block elements
transition elements are f block elements
Inner
general configuration ns Cn 1 d n 2 f n 6 or n 7
f
b series Actinides radioactive Th 90 to Lr 103
P E R I OD S 13 9 2019
Li Be B C N O F
2nd 2 I 2,2 2,3 2,4 2,5 2,6 217
3 4 5 6 7 8 9
a number of shellsincrease
b Shielding effect is more due to number of inner shells increasing down thegroup
Li 2 I no of shellsincrease
Na 2 8 I s p d 7 f nuclear charge decrease
K 2,8 8 1 Order of Shielding Effect shielding effect increases
R 2 8 18 1
Cs
2 Vanderwaals Radius
one half distance between the centres of nuclei of 2 nearest like atoms belonging to
adjacent molecule
H Ce Ce H
molecule
3 Metallic Radius
one half the distance between the centres 2 adjacent atomsin metallic crystals
e
order of size
M M
4 tonicRadius
cation radius L atomicradius because positive charge increases nuclear charge will increase
13
Ex Fe C Fe L Fe
3 2 12 2
Increasing order Al Na O O My K S
17 9 2019
Effective Nuclear Charge N S V
N 2 I
Zegg I Z S onlyappliestoperiod C 2 4
atomicno no ofcoreelectrons f 2 y
Group
2 I Li Be B C N O F
2,1 2,2 2,3 2,4 2,5 2,6 2,7
2 8 I Na Mg Al
ii to iz lo
z Group ShellsT core e T S E T Nocharged
2 8 8 I K Period nochange nochange t T
is is
Ex Na Ng S Ce
11 10 1210 1610 17 10
I 2 6 7
Ionization Energy
the amount of energy required to remove an electron from a gaseous neutral atom
Xg 1 Energy X t le
General Trend
Period Increases Zegg T
Group Decreases Atomic size S E T
He
Ne
First N F
1E H Be c
8
B
Li
atomic number
Electron
Affinity
amount of energy releasedwhen an electron is added to a gaseous neutral atom
X g t e X g Energy
Note E A of Cl F
E A of S O
E A Of noble gases is considered as zero
Cl F
2ndPeriod Li Be B C N O F
60 70 27 122 70 141 328
1525 2ps
Electro Negativity
tendency of an atom to attract a shared pair of e in a covalent bond
GeneralTrend
Period Increases
Group Decreases
Melting Points depends on structure bonding types of force of attraction that exists in the
element
Group I Group 17
Li 7 Na K Rb Cs F L Ce s Br C I
strength of metallic bonding decreases M.p increases down thegroup because
due to increase in atomicsize atomic weight increases
Carbon
Sg Pc
6 Silicon
ni 14 Size ofmolecule
E is largerelatively
13
5 12
4 it
3
1 2 15 16 17 IS
Atomic number
Group 1 Alkalimetals
more reactive metals
good conductors low density lightmetals
these metals are stored in liquid paraffin not to get exposed to air moisture
these are good reducing agents
Li H2O LiOH Hz
2 Na t Clz 2NaCl
2 K t Br s 2KBr
Group 17 Halogens
Mostreactive non metals
act as goodoxidizing agents
reactivity decreasesdown the group
F 7 Cl Br 7 I F Ce Br I At
gases liquid solids
Displacement reactions among halogen
Cl 1 2KBr 2KCe t Br
Br t Kce no reaction
I
AgtNOj Natch NANO Agee
i
soluble soluble Insoluble Precipitate
20 9 2019
Trends across Period 3
Practice Qs
Spectrochemical series arranged in the order of their ability to split the d orbital
t
CO CN NHz OH H2O Ce SZ Br I
Red 31
In absorption spectrum of CT Hao 6 is shown below use the colour wheel to suggestcolour of
the complex ion
Linux duty de
Energy is absorbed light OE
o
E
Et dnydnzdyz
4004501082551506006150 tootoodoo
In ferromagnetism e of atoms are grouped into domains parallel throughout the compound
r
Il radom iron nNiine foobait
OE OE high frequency