Page 14 - Chemistry ICSE Class X
P. 14
Periodic Properties and
1 Variations of Properties
(Physical and Chemical)
;QW JCXG TGCF CDQWV VJG RGTKQFKE ENCUUKſECVKQP QH GNGOGPVU KP ENCUU +:
CONTENTS *GTG YG TGXKGY VJG OCKP HGCVWTGU QH VJG /QFGTP 2GTKQFKE 6CDNG
In 1911 after the discovery of electron and proton and the
ͻ DŽĚĞƌŶ ůŽŶŐ ĨŽƌŵ ƉĞƌŝŽĚŝĐ ƚĂďůĞ
FGXGNQROGPV QH PWENGCT OQFGN QH VJG CVQO VJG &WVEJ RJ[UKEKUV # XCP FGP
ͻ WĞƌŝŽĚŝĐ ƉƌŽƉĞƌƟĞƐ ĂŶĚ ƚŚĞŝƌ Broek suggested that the atomic number should prove a better basis of
ǀĂƌŝĂƟŽŶƐ ŝŶ ŐƌŽƵƉƐ ĂŶĚ ƉĞƌŝŽĚƐ
ENCUUKſECVKQP QH GNGOGPVU KP RNCEG QH CVQOKE OCUU
ͻ ƚŽŵŝĐ ƐŝnjĞ +P * ) , /QUGNG[ 'PINCPF EQPſTOGF VJCV VJG RTQRGTVKGU QH
ͻ DĞƚĂůůŝĐ ĐŚĂƌĂĐƚĞƌ GNGOGPVU FGRGPF QP CVQOKE PWODGT TCVJGT VJCP CVQOKE OCUU 6JKU NGF
ͻ EŽŶŵĞƚĂůůŝĐ ĐŚĂƌĂĐƚĞƌ to the modern periodic law 6JG OQFGTP RGTKQFKE NCY UVCVGU VJCV when
the elements are arranged in the increasing order of atomic number,
ͻ /ŽŶŝƐĂƟŽŶ ĞŶĞƌŐLJ ;Žƌ /ŽŶŝƐĂƟŽŶ
ƉŽƚĞŶƟĂůͿ elements with similar properties occur at regular interval.
That is, “The properties of elements are periodic function of their
ͻ WĞƌŝŽĚŝĐ ǀĂƌŝĂƟŽŶ ŽĨ /ŽŶŝƐĂƟŽŶ
ĞŶĞƌŐLJ atomic numbers.”
ͻ ůĞĐƚƌŽŶ ĂĸŶŝƚLJ
Modern Long Form Periodic Table
ͻ WĞƌŝŽĚŝĐ ǀĂƌŝĂƟŽŶ ŽĨ ĞůĞĐƚƌŽŶ ĂĸŶŝƚLJ
ͻ ůĞĐƚƌŽŶĞŐĂƟǀŝƚLJ 6CMKPI CVQOKE PWODGT CU VJG DCUKU QH ENCUUKſECVKQP QH GNGOGPVU $QJT
ͻ &ĂĐƚŽƌƐ ĂīĞĐƟŶŐ ĞůĞĐƚƌŽŶĞŐĂƟǀŝƚLJ constructed a periodic table known as the Long Form Periodic Table
KP
ͻ WĞƌŝŽĚŝĐ ǀĂƌŝĂƟŽŶ ŽĨ
ĞůĞĐƚƌŽŶĞŐĂƟǀŝƚLJ In 1984, IUPAC (International Union of Pure and Applied Chemistry)
ͻ ZĞůĂƟŽŶƐŚŝƉ ďĞƚǁĞĞŶ ĂƚŽŵŝĐ recommended that the groups in the long form periodic table be numbered
ŶƵŵďĞƌ ;ƉƌŽƚŽŶ ŶƵŵďĞƌͿ ĂŶĚ HTQO VJG NGHV CU VQ
ĂƚŽŵŝĐ ŵĂƐƐ ;ŵĂƐƐ ŶƵŵďĞƌͿ ĨŽƌ ůŝŐŚƚ The long form periodic table relates the position of an element to its
ĞůĞŵĞŶƚƐ
GNGEVTQPKE EQPſIWTCVKQP
ͻ ůŬĂůŝ ŵĞƚĂůƐ ĂŶĚ ŚĂůŽŐĞŶƐ
What are the features of the long form periodic table
(IUPAC)
The general features of the Long Form Periodic Table (IUPAC 1984) are:
Groups in the periodic table. The long form periodic table
+72#% EQPUKUVU QH XGTVKECN EQNWOPU ECNNGF ITQWRU 6JWU
there are 18 groups in long form periodic table 6JGUG ITQWRU CTG
numbered 1 to 18 from the left, using Arabic numerals +P VJG $QJTŏU
long form periodic table, the groups are numbered from left as
IA, IIA, IIIB, IVB, VB, VIB, VIIB, VIII, IB, IIB, IIIA, IVA, VA, VIA, VIIA CPF
H.G.J. Moseley Blocks of elements in the periodic table. The periodic table is divided
into HQWT DNQEMU DCUGF QP GNGEVTQPKE EQPſIWTCVKQP
s-block. 6JKU DNQEM EQPUKUVU QH ITQWRU CPF
,LJĚƌŽŐĞŶ ŚĂƐ ďĞĞŶ ĂƐƐŝŐŶĞĚ Ă
ƐĞƉĂƌĂƚĞ ƉŽƐŝƟŽŶ Ăƚ ƚŚĞ ƚŽƉ ŽĨ ŐƌŽƵƉ ϭ͘ p-block. 6JKU DNQEM EQPUKUVU QH ITQWRU VQ
The elements belonging to s- and p-blocks are called main group
elements
d-block. 6JKU DNQEM EQPUKUVU QH ITQWRU VQ 'NGOGPVU N[KPI KP
this block are called transition elements
f-block. 6JKU DNQEM KU RNCEGF DGNQY VJG OCKP VCDNG 6JG GNGOGPVU
belonging to this group are called inner-transition elements