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Chemestry, element-Zr, Zirconium

March 24, 2016 | Author: | Posted in chemistry, life sciences

Zirconium

Zirconium (assigned the symbol Zr , a chemical element with the atomic number of 40 , is a transition metal element found in Group IVa of the periodic table

Zirconium is a rare light-grayish lustrous metal . It is corrosion-resistant because it forms an oxide film on its surface which inhibits further corrosion . It is also highly resistant to heat . It is a strong metal , and has a hardness similar to that of copper , but is lighter than steel . It is also highly malleable and ductile . It is rarely found in its pure [banner_entry_middle]

form because of its high reactivity to oxygen nitrogen , carbon , and silicon

Atomic structure

Number of Energy Levels 5

First Energy Level 2 Second Energy Level 8

Third Energy Level 18

Fourth Energy Level 10

Fifth Energy Level 2

Electron Configuration 1s2

2s2p6 3s2p6d10 4s2p6d2 5s2

Valance Electrons 4d2

5s2

Number of Electrons (with no charge ) 40

Number of Neutrons (most common /stable nuclide : 51

Number of Protons 40 Figure 1 . Shell Model (Yinon

Figure 2 . Electron Dot Model

Figure 3 . Crystal Structure

Atomic Radius : 2 .16E

Atomic Volume : 14 .1cm3 /mol

Covalent Radius : 1 .45E

Crystal Structure : Hexagonal

Filling Orbital : 4d2

Ionic Radius : 0 .72E

Ionization Energy : 6 .634 eV

Number of Stable Isotopes : 4

Oxidation States 4

Estimated Crustal Abundance : 1 .65CH102 milligrams per kilogram

Estimated Oceanic Abundance : 3CH10-5 milligrams per liter

Estimated Abundance in the Sun 560 milligrams per liter (Relative to H 1E12

PHYSICAL PROPERTIES OF ZIRCONIUM

Physical Properties

Atomic Mass Average 91 .224

Boiling Point 4650K 4377 ?C 7911 ?F Coefficient of lineal thermal expansion /K-1 5 .78E-6

Conductivity Electrical 0 .0236 106 /cm

Thermal 0 .227 W /cmK

Density 6 .51g /cc 300K

Elastic Modulus Bulk 89 .8 /GPa

Rigidity 35 /GPa

Youngs 98 /GPa

Enthalpy Atomization 598 kJ /mole 25 ?C

Fusion 20 .9 kJ /mole

Vaporization 581 .6 kJ /mole

Flammablity Class Combustible

Freezing Point (see melting point

Hardness Scale Brinell 650 MN m-2

Mohs 5

Vickers 903 MN m-2

Heat of Vaporization 58 .2kJ /mol

Melting Point 2125K 1852 ?C 3366 ?F

Molar Volume 14 .06 cm3 /mole

Physical State (at 20 ?C 1atm : Solid Specific Heat 0 .27J /gK

Vapor Pressure 0 .00168Pa 1852 ?C CHEMICAL PROPERTIES OF ZIRCONIUM

Zirconium is difficult to separate from hafnium using chemical means since it does not dissolve in alkalis and acids . It is similar to silicon in its chemical properties

Reaction with air . In its solid state , zirconium is relatively stable although it can spontaneously ignite with air at high temperatures when finely divided

Zr (s O2 (g ? ZrO2 (s

Reaction with halogens . At elevated temperatures , zirconium reacts halogens to form zirconium (IV ) halides

Zr (s 2F2 (g ? ZrF4 (s ) [white]

Zr (s 2Cl2 (g ? ZrCl4 (l ) [white]

Zr (s 2Br2 (g ? ZrBr4 (s ) [white]

Zr (s 2I2 (g ? ZrI4 (s ) [white]

Chemical Properties

Electrochemical Equivalent 0 .8509g /amp-hr Electron Work Function 4 .05eV

Electronegativity 1 .33 (Pauling 1 .22 (Allrod Rochow

Heat of Fusion 16 .9kJ /mol

Incompatibilities Potassium nitrate , oxidizers… [banner_entry_footer]

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