Transcript CHAPTER - 4 STRUCTURE OF ATOM

Tutorial
1) Using Slater’s rule confirm that the experimentally observed
electronic configuration of K (Z = 19), 1s2 2s2 2p6 3s2 3p6 4s1, is
energetically more stable than the configuration 1s2 2s2 2p6 3s2 3p6 3d1.
2) Use Slater’s rules to estimate values of Zeff for (a) a 4s and (b) a 3d
electron in a V atom. Using your answer, explain why the valence
configuration of the ground state of a V+ ion is likely to be 3d34s1 rather
than 3d24s2.
3) Assume three p-block elements A (Z = 6), B (Z = 7) and C (Z = 8)
having ground state electronic configuration 1s22s22p2 , 1s22s22p3 and
1s22s22p4 respectively. The increase in Zeff between A and B is 0.69
whereas the increase between B and C is only 0.62. Suggest a reason
why the increase in Zeff for a 2p electron is smaller between B and C
than between A and B given the configurations of the atoms listed
above.
Period
f block elements
Noble Gas
Inner transition elements
Halogen
Group
Alkali Earth Metal
Alkali Metal
Transition elements
np6
ns1
d7
d8
d10
f block elements
np5
d6
np4
d5
np3
d2 d3
s1
d10
np2
np1
ns2
d1
s1
d5
Noble Gases
1s2
He
2
1s22s22p6
Ne
10
1s22s22p63s23p6
Ar
18
1s22s22p63s23p64s23d104p6
Kr
36
1s22s22p63s23p64s23d104p65s24d105p6
Xe
54
1s22s22p63s23p64s23d104p65s24d10 5p66s24f14 5d10 6p6
Rn
86
Noble Gases
np6
Noble Gas
Noble Gases
 Neon (Ne) and the elements below it in Group 18 have eight
electrons in their outer energy levels.
 Their energy levels are stable, so they do not combine easily with
other elements.
Alkali Metals
H
1
Li
3
Na
11
1s1
1s22s1
1s22s22p63s1
K
1s22s22p63s23p64s1
19
Rb
37
1s22s22p63s23p64s23d104p65s1
Cs
55
1s22s22p63s23p64s23d104p65s24d10 5p66s1
Fr
87
1s22s22p63s23p64s23d104p65s24d105p66s24f
145d106p67s1
Alkali Metals
ns1
Alkali Metal
Alkali Metals
 The alkali metals form compounds that are similar to each
other.
 Alkali metals each have one outer energy level electron.
 It is this electron that is removed when alkali metals react.
 The easier it is to remove an electron, the more reactive the
atom is.
 Unlike halogens, the reactivities of alkali metals increase down
the group.
Ionization Energies of Elements
np6
ns2
ns1
np5
np4
Ionization Energies of Elements
Ionization energy increases across a period and decreases down a group.
The variation of first ionization
energy (in kilojoules per mole)
through the main groups of the
periodic table.
Why ionization energy of N/P is higher than O/S?
Ionization Energies of Elements
The values of the first ionization energies of the elements up to Rn.
Ionization energy increases across a period and decreases
down a group.
Halogens
np6
np5
Noble Gas
Halogen
Halogens
 Fluorine is the most reactive of the halogens because its outer
energy level is closest to the nucleus.
ELECTRON AFFINITY
Electron affinities are highest for elements near fluorine, particularly the halogens.
Electronegativity increases across a
period and decreases down a group.
ELECTRON AFFINITY
Electron affinities are highest for elements near fluorine, particularly the halogens.
Electronegativity increases across a period and decreases down a group.
Periodic Properties
Books:
Books:
1) INORGANIC CHEMISTRY: Duward Shriver and Peter Atkins.
2) Inorganic Chemistry: Principles of Structure and Reactivity by James E. Huheey,
Ellen A. Keiter and Richard L. Keiter.
3) Inorganic Chemistry: Catherine Housecroft, Alan G. Sharpe.