Periodic Table

Ores

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Ores of zinc (Zn):
Zincite (ZnO), Zinc blende or spharelite (ZnS), Zincspar or clalmine (ZnCO₃), Willemite (Zn₂SiO₄).

Ores of silver (Ag):
Horn silver (AgCl), Argentite or silver glance (Ag₂S), Pyrargyrite or ruby silver (3Ag₂S-Sb₂S₃), Stromeyerite or silver copper glance {(Cu,Ag)₂S}.

Ores of aluminium (Al):
Corundum, Ruby, Sapphire, Emerald (Al₂O₃)
Diaspore (Al₂O₃.H₂O), Bauxite (Al₂O₃.2H₂O) (Most important ore), Gibbsite (Al₂O₃.3H₂O), Cryolite (Na₃AlF₆) (2^nd most important ore), Alum stone {K₂SO₄.Al₂(SO₄)₃.4Al(OH)₃},Turquoise {AlPO₄.Al(OH)₃.H₂O}, Felspar (KAlSi₃O₈).

Ores of lead or plumbum (Pb):
Galena (PbS), Anglesite (PbSO₄), Cerussite (PbCO₃),Lanarkite (PbO.PbSO₄).

Ores of magnesium (Mg):
Magnesite (MgCO₃) (Chief ore), Dolomite (MgCO₃.CaCO₃), Kiesserite (MgSO₄.H₂O), Epsom salt (₄.7H₂O), Carnallite (KCl.MgCl₂.6H₂O), Asbestos {CaMg₃(SiO₃)₄}.

Ores of calcium (Ca):
Calcite or calcspar or Limestone (CaCO₃), Dolomite (MgCO₃.CaCO₃), Gypsum (CaSO₄.2H₂O), Fluorspar (CaF₂), Fluoraspatite {3Ca(PO₄).CaF₂}, Phosphorite {Ca₃(PO₄)₂}.

Ores of Iron (Fe):
Magnetite (Fe₃O₄) (main ore), Haematite (Fe₂O₃), Limonite (Fe₂O₃.3H₂O), Siderite or sepathic iron (FeCO₃), Iron pyrites (FeS₂), Chalcopyrites (CuFeS₂).

Ores of copper (Cu):
Copper pyrites (CuFeS₂) (Main ore), Melachite {CuCO₃.Cu(OH)₂}, Cuprite (Cu₂O), Copper glance (Cu₂S) .

Ores of tin (Sn):
Cassiterite (SnO₂).

Ores of mercury (Hg):
Cinnabar (HgS).

Ores of Sodium (Na):
Rock salt (NaCl) (main ore), Chile saltpetre (NaNO₃), Glaubers salt (Na₂SO₄.10H₂O), Trona (Na₂CO₃.2NaHCO₃.3H₂O), Natron (Na₂CO₃.H₂O), Tincal (Borax) (Na₂B₄O₇.10H₂O), Cryolite (NaAlSi₃O₈), Soda feldspar (NaAlSi₃O₈), Feldspar (Na₃AlSiO₈).

Ores of Lithium (Li):
Spodumene (LiAlSi₂O₆, Lepidolite {(Li,Na,K)₂Al₂(SiO₃)₃.F(OH)}.

Ores of chromium (Cr):
Chromite (Cr₂O₃.FeO).

Classification on basis of complete or incomplete electron shells

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Division into s,p,d and f block elements

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S block elements
The element in which the last electron enters the s-subshell is called s-block element.

S-block consists of group IA ,group IIA and the element Helium.

Group IA consists of Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Caesium(Cs) and Francium(Fr).

Group IIA consists of Berrylium(Be), Magnesium(Mg), Calcium(Ca), Strontium(Sr), Barium(Ba) and Radium(Ra).

P block elements
The element in which the last electron enters the p-subshell is called p-block element.

Element of p-block belong to group IIIA, IVA, VA, VIA, VIIA and VIIIA.

The p block elements are characterised by the ns²np^x valence shell electronic configuration where x varies from 1 to 6 and n varies from 2 to 6.

P-Block elements
Group Period	IIIA	IVA	VA	VIA	VIIA	VIIIA
2	B	C	N	O	F	Ne
3	Al	Si	P	S	Cl	Ar
4	Ga	Ge	As	Se	Br	Kr
5	In	Sn	Sb	Te	I	Xe
6	Ti	Pb	Bi	Po	As	Rn

D-Block elements
The element in which the last electron enters the d-subshell is called d-block element. These elements are also called transition elements and are metals.

There are four series of d-block elements.

The last electron enters the 3d subshell in 10 elements. The series formed by them is present in 4^th period. This series is called 3d transition series. The series starts from atomic number 21 and ends with atomic number 30. The elements are Sc(21), Ti, V, Cr, Mn, Fe, Co, Ni, CU and Zn(30).

The last electron enters the 4d subshell in 10 elements. The series formed by them is present in 5^th period. This series is called 4d transition series. the series starts from stomic number 39 and ends with atomic number 48. The elements are Y(39), Zr, Nb, Mo, Te, Ru, Rh, Pd, Ag and Cd(48).

The last electron enters the 5d subshell in 10 elements. The series formed by them is present in 6^th period. This series is called 5d transition series. The series has atomic number 57 and 72 to 80. The elements are La(57), Hf(72), Ta, W, Re, Os, Ir, Pt, Au and Hg(80).

The 6d series corresponds to filling of 6d subshell. The series has element Ac(89) and elements with atomic number 104 onwards.

General characteristics of Periods

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Characteristics of periods.

Valency The valency of the elements increases from 1 to 4 then falls back to 1, with respect to hydrogen, in each short periods. The valency of the element with respect to oxygen increases from 1 to 8.

Properties The properties of element differ very much from each other in a period.

Size of atoms Size of atoms decreases from left to right in a period.

Number of electron shells The number of electron shells in a period remains same.

Metallic character The metallic character decreases from left to right in a period. As metallic character decreases, basis character also decreases.

Ex. In 3^rd period
Na, Mg, Al           Si, P, S, Cl
metals               non metals
Na₂O              MgO      Al₂O₃         SiO₂            P₂O₅      SO₃          Cl₂O₇
Strongly basic    Basic    Amphoteric   Feebly acidic   Acidic    More acidic  Most acidic

General characteristics of Groups

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Characteristics of groups.

Valency The valency of all the elements in the same group is the same. The valency of the element with respect to oxygen is equal to its group number.

Properties Physical and chemical properties of all the elements in a group are very similar. But, there is a regular gradation of properties when we move from top to bottom.
1. The base forming tendency increases in going from top to bottom in group IA (alkali metals).
2. The reactivity of halogens (group VIIA) decreases as we pass from F to I.

Size of atoms Size of atoms increases when we move down a group.

For ex:Atomic size increases from Li to Cs in group IA
              Li<Na<K<Rb<Cs<Fr

Number of electron shells The number of electron shells increases by one when we move down in a group and equals the number of period.


Elements     Electronic configuration  No of shells
 Li           2,1                          2
 Na           2,8,1                        3
 K            2,8,8,1                      4
 Rb           2,8,18,8,1                   5
 Cs           2,8,18,18,8,1                6 
 Fr           2,8,18,32,18,8,1             7

Metallic character The metallic character of the elements increases when we move fron top to bottom in a group. This is visible in groups IVA, VA and VIA, which begin with nonmetals and end with metals. Basic character increases when metallic character increases. So, the oxides of elements become more and more basic when we move from top to bottom.
```
Ex. In group VA
N,P           As,Sb              Bi
Non metals    Metalloids         Metal
N₂O₃,P₂O₅      As₂O₃,Sb₂O₃         Bi₂O₃
Acidic        Amphoteric         Basic
```

7th Period

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The elements of this period starts from Fr (Z = 87) and are increasing. The elements are Francium, Radium, Actinium, Thorium, Palladium, Uranium, Neptunium, Plutonium, Americium, Curium, Berkelium, Californium, Einsteinium, Fermium, Mendelevium, Nobelium, Lawrencium, Rutherfordium, Dubnium,

6th Period

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Sixth period contains 32 elements from Cs (Z = 55) to Rn (Z = 86). The elements are Cesium, Barium, Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold ,Mercury , Thallium, Lead, Bismuth, Polonium, Astatine and Radon.

5th Period

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There are 18 elements in the period 5. They are Rubidium, Strontium, Ytterbium, Zirconium, Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver, Cadmium, Indium, Tin, Antimony, Tellurium, Iodine and Xenon.

4th Period

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Fourth period has 18 elements. They are Potassium, Calcium, Scandium, Titanium, Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Gallium, Germanium, Arsenic, Selenium, Bromine and Krypton.

3rd Period

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Third period has 8 elements. They are Sodium, Magnesium, Aluminum, Silicon, Phosphorous, Sulfur, Chlorine and Argon.

2nd Period

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Second Period has 8 elements. They are Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine and Neon.

Ist Period

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First period has two elements. They are Hydrogen and Helium.

Group VIII

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Zero Group

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The elements of this group are called inert gases.

There are 6 elements present in this group.

The elements are Helium(He), Neon(Ne), Argon(Ar), Krypton(Kr), Xenon(Xe) and Radon(Rn)

The elements of this group belong to p-block except helium (helium belongs to s- block).


Element    Atomic number  Electronic configuration        
He         2              2 or 1s²
Ne         10             2,8 or 1s²2s²2p⁶
Ar         18             2,8,8 or 1s²2s²2p⁶3s²3p⁶
Kr         36             2,8,18,8 or 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶
Xe         54             2,8,18,18,8 or 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p⁶
Rn         86             2,8,18,32,18,8 or 1s²2s²2p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰4f¹⁴5s²5p⁶5d¹⁰6s²6p⁶

The gases in the order of their discovery are
ARGON(18)
HELIUM(2)
NEON(10)
KRYPTON(36)
XENON(54)
RADON(86)

Group VIII

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There are three triads in group VIII.

Group VIII : first triad

There are 3 elements present in this triad.

The elements of this triad belong first transition series and are called ferrous metals.

The elements are Iron(Fe), Cobalt(Co) and Nickel(Ni)

The elements of this group belong to d-block.


Element    Atomic number  Electronic configuration         Valence shell(Elec. conf.)
Fe         26             2,8,14,2 or [Ar]3d⁶4s²             3d⁶4s²
Co         27             2,8,15,2 or [Ar]3d⁷4s²             3d⁷4s²
Ni         28             2,8,16,2 or [Ar]3d⁸4s²             3d⁸4s²

Group VIII : second triad

There are 3 elements present in this triad.

The elements of this triad along with 3^rd triad are known as platinum metals. The elements of this triad are known as light platinum metals.

The elements are Ruthenium(Ru), Rhodium(Rh) and Palladium(Pd)

The elements of this group belong to d-block.


Element    Atomic number  Electronic configuration   Valence shell(Elec. conf.)
Ru         44             [Kr]5s¹4d⁷                  5s¹4d⁷
Rh         45             [Kr]5s¹4d⁸                  5s¹4d⁸
Pd         46             [Kr]5s⁰4d¹⁰                 5s⁰4d¹⁰

Group VIII : third triad

There are 3 elements present in this triad.

The elements of this triad along with 3^rd triad are known as platinum metals. The elements of this triad are known as heavy platinum metals.

The elements are Osmium(Os), Iridium(Ir) and Platinum(Pt)

The elements of this group belong to d-block.


Element    Atomic number  Electronic configuration   Valence shell(Elec. conf.)
Os         76             [Xe]6s²4f¹⁴5d⁶               6s²4f¹⁴5d⁶
Ir         77             [Xe]6s²4f¹⁴5d⁷               6s²4f¹⁴5d⁷
Pt         78             [Xe]6s¹4f¹⁴5d⁹               6s¹4f¹⁴5d⁹

Group VII

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VIIA group

There are 5 elements present in this group.

The elements are Fluorine(F), Chlorine(Cl), Bromine(Br), Iodine(I) and AStatine(At)

The elements of this group belong to p-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
F          9              2,7 or [He]2s²p⁵                2s²p⁵
Cl         17             2,8,7 or [Ne]3s²p⁵              3s²p⁵
Br         35             2,8,18,7 or [Ar]4s²p⁵           4s²p⁵
I          53             2,8,18,18,7 or [Kr]5s²p⁵        5s²p⁵
At         85             2,8,18,32,18,7 or [Xe]6s²p⁵     6s²p⁵

Group VI

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VIA Group

There are 5 elements present in this group.

The elements are Oxygen(O), Sulphur(S), selenium(Se), Tellurium(Te) and Polonium(Po)

The elements of this group belong to p-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
O          8              2,6 or [He]2s²p⁴                2s²p⁴
S          16             2,8,6 or [Ne]3s²p⁴              3s²p⁴
Se         34             2,8,18,6 or [Ar]4s²p⁴           4s²p⁴
Te         52             2,8,18,18,6 or [Kr]5s²p⁴        5s²p⁴
Po         84             2,8,18,32,18,6 or [Xe]6s²p⁴     6s²p⁴

Group V

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Group VA

There are 5 elements present in this group.

The elements are Nitrogen(N), Phosphorous(P), Arsenic(As), Antimony(Sb) and Bismuth(Bi)

The elements of this group belong to p-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
N          7              2,5 or [He]2s²p³                2s²p³
P          15             2,8,5 or [Ne]3s²p³              3s²p³
As         33             2,8,18,5 or [Ar]4s²p³           4s²p³
Sb         51             2,8,18,18,5 or [Kr]5s²p³        5s²p³
Bi         83             2,8,18,32,18,5 or [Xe]6s²p³     6s²p³

Group IV

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Group IVA

There are 5 elements present in this group.

The elements are Carbon(C), Silicon(Si), Germanium(Ge), Tin(Sn) and Lead(Pb)

The elements of this group belong to p-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
C          6              2,4 or [He]2s²p²                2s²p²
Si         14             2,8,4 or [Ne]3s²p²              3s²p²
Ge         32             2,8,18,4 or [Ar]4s²p²           4s²p²
Sn         50             2,8,18,18,4 or [Kr]5s²p²        5s²p²
Pb         82             2,8,18,32,18,4 or [Xe]6s²p²     6s²p²

Group III

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Group IIIA

There are 5 elements present in this group.

The elements are Boron(B), Aluminium(Al), Gallium(Ga), Indium(In) and Thallium(Th)

The elements of this group belong to p-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
B          5              2,3 or [He]2s²p¹                2s²p¹
Al         13             2,8,3 or [Ne]3s²p¹              3s²p¹
Ga         31             2,8,18,3 or [Ar]4s²p¹           4s²p¹
In         49             2,8,18,18,3 or [Kr]5s²p¹        5s²p¹
Th         81             2,8,18,32,18,3 or [Xe]6s²p¹     6s²p¹

Group II

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Group IIA

The elements of this group are called alkaline earth metals.

There are 6 elements present in this group.

The elements are Berryllium(Be), Magnesium(Mg), Calcium(Ca), Strontium(Sr), Barium(Ba) and Radium(Ra)

The elements of this group belong to s-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
Be         4              2,2 or [He]2s²               2s²
Mg         12             2,8,2 or [Ne]3s²             3s²
Ca         20             2,8,8,2 or [Ar]4s²           4s²
Sr         38             2,8,18,8,2 or [Kr]5s²        5s²
Ba         56             2,8,18,18,8,2 or [Xe]6s²     6s²
Ra         88             2,8,18,32,18,8,2 or [Rn]7s²  7s²

Group I

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Group IA

The elements of this group are called alkali metals.They are called alkali metals because they form oxides and hydroxides with water to produce alkalies.

There are 6 elements present in this group (excluding hydrogen whose position is also considered in group VII).

The elements are Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Caesium(Cs) and Francium(Fr)

The elements of this group belong to s-block.


Element    Atomic number  Electronic configuration  Valence shell(Elec. conf.)
Li         3              2,1 or [He]2s¹               2s¹
Na         11             2,8,1 or [Ne]3s¹             3s¹
K          19             2,8,8,1 or [Ar]4s¹           4s¹
Rb         37             2,8,18,8,1 or [Kr]5s¹        5s¹
Cs         55             2,8,18,18,8,1 or [Xe]6s¹     6s¹
Fr         87             2,8,18,32,18,8,1 or [Rn]7s¹  7s¹

Extended or Long form of periodic table

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Mosley's modern periodic table

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Modern periodic law put forward by Mosley states that if the elements are arranged in the increasing order of atomic numbers then the properties of the elements repeat after a fixed interval.

Irregularities disappeared of Mendeleev's table in this table.They are:

Position of hydrogen: The dual role of hydrogen is explained by the fact that it has one electron in its outer orbit. It can gain as well loose this electron easily.

Anomalous pairs: The anomalous pairs which were present in Mendeleev's table disappeared in this table.
1. Argon At. No. 18 and mass no. 40
  Potassium At. No. 19 and mass no. 39
2. Cobalt At. No. 27 and mass no. 59.9
  Nickel At. No. 28 and mass no. 58.6
3. Thorium At. No. 52 and mass no. 127.6
  Iodine At. No. 53 and mass no. 126.9
4. Thorium At. No. 90 and mass no. 232.12
  Palladium At. No. 91 and mass no. 231
Position of rare earths:The arrangement of extra-nuclear electrons in all the rare earth elements can be represented as 2,8,18,(18+x),9,2, where x varies from 0(for La) to 14 (for Lu).This arrangement justifies that they have the same valency and similar chemical properties. It also justifies their grouping at the same place.

Position of isotopes: All the isotopes occupy the same position as they have the same atomic number.

Mendeleev's Periodic table

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Mendeleev's Periodic law states that the properties of the elements are the periodic function of their atomic weights.

Defects of Mendeleev's periodic table

Position of hydrogen: Hydrogen shows the properties of both the alkali metals and halogens. Its position is therefore anomalous.

Order changes in case of four pairs of elements: The element with higher atomic weight precede the element with lower atomic weight. This was done to place them at suitable position in the periodic table according to their properties. There are four such pairs.
1. Argon with atomic weight 40 is placed before potassium with atomic weight 39.0 .
2. Cobalt with atomic weight 59.9 is placed before nickel with atomic weight 58.6 .
3. Tellurium with atomic weight 127.6 is placed before iodine with atomic weight 126.9.
4. Thorium with atomic weight 232.12 is placed before palladium with atomic weight 231 .

Position of isotopes: Isotopes cannot be placed in order if the elements are arranged in the increasing order of their atomic weight.

The properties of the same group of elements is not same. Elements like copper and mercury; silver and thallium ; and barium and lead are placed in different groups although their properties resembles. Cu, Ag and Au are grouped along with the alkali metals although they do not have properties like them. Also, manganese is grouped with halogens.

Position of lanthanides and actinides. Lanthanides ( At. no 57 to 71) has been placed at one place in group III and period 6. Actinides ( At. no 89 to 103) are placed at one place in group III and period 6.

The group does not represent valency for all the elements.