ppt kimia unsur se te po uuh

Se, Te, Po dan Uuh

By:1. Dewi Shinta (13630002)2. Susanti Anugrah R (13630004)3. Sinta Ayunda (13630012)4. Muhamad Yorda (13630016)5. Muhammad Ansori (13630019)6. Khurrotul Ainia (13630022)7. A Fiqri Amrullah (13630026)8. Khoirul Anwar (13630029)9. Faizatul Hazanah (13630031)

WHAT WILL WE LEARN?

SELENIUM (Se)HISTORY

JONS JAKOB BERZILIUS

Selenium was discovered by Jöns Jacob Berzelius at Stockholm in 1817. He had shares in a sulfuric acid works and he was intrigued by a red-brown sediment which collected at the bottom of the chambers in which the acid was made. At first he thought it was the element tellurium because it gave off a strong smell of radishes when heated, but he eventually realised that it was in fact a new element. He also noted that it was like sulfur and indeed had properties intermediate between sulfur and tellurium. Berzelius found that selenium was present in samples of tellurium and gave that element its characteristic smell.

Group 4

SELENIUM (Se)PROPERTIESatomic volume 16,5 Cm3/mol

Oxidation number -2,4,6

Boiling point 685°C, 1265°F, 958 K

Melting point 220.8°C, 429.4°F, 494 K

heat capacity 0,32 Jg-1K-1

covalent radius 1,16 Å

crystal structure hexagonal

State at 20°C Solid

Density (g cm−3) 4.809

Key isotopes 80Se

electrical conductivity 8 x 106 ohm-1cm-1

electronegativity 2,55

formation enthalpy 5,54 kJ/mol

thermal conductivity 2,04 Wm-1k-1

ionization potential 9,752 V

Group 4

SELENIUM (Se)Chemical reaction

Reaction of selenium with airSelenium burns in air to form the solid dioxide selenium(IV) oxide, SeO2.

Se8(s) + 8O2(g) → 8SeO2(s)

Reaction of selenium with the halogens

Selenium reacts with fluorine, F2, and burns to form the hexafluoride selenium(VI) fluoride.

Se8(s) + 24F2(g) → 8SeF6(l) [orange]

Group 4

SELENIUM (Se)Chemical reaction

Group 4

Reaction of selenium with acids

Selenites acids can also be made directly by the reaction of selenium with nitric acid. Reaction: 3Se + 4HNO3 → 3H2SeO3 + 4 NO

Reaction of selenium with metal(Selenida)

3Se + 2 Al → Al2Se3

Al2Se3 + 6H2O → 2Al(OH)3

Se + Fe → SeFe

Selenium exists in several allotropes (black, red, and gray (not pictured) allotropes) that interconvert upon heating and

cooling carried out at different temperatures and rates. As prepared in chemical reactions, selenium is usually an

amorphous, brick-red powder. When rapidly melted, it forms the black, vitreous form, which is usually sold industrially as

beads. The structure of black selenium is irregular and complex and consists of polymeric rings with up to 1000 atoms per ring. Black Se is a brittle, lustrous solid that is

slightly soluble in CS2. Upon heating, it softens at 50 °C and converts to gray selenium at 180 °C.

SELENIUM (Se)allotropes

Group 4

Black Se

Red Se

SELENIUM (Se)

Selenium is found in several rare minerals such as kruksit and klausthalit. Se also obtained from flue dust produced during the roasting sulphide ores such as PbS,

CuS, or FeS. The dust is trapped by means of an electrostatic precipitator. Selenium also occur in the

native form together with S . Most of the world’s selenium is obtained from the anode muds produced during the electrolytic refining of copper. These muds are either roasted with sodium carbonate or sulfuric

acid, or smelted with sodium carbonate to release the selenium.

HOW TO OBTAIN!!

Group 4

SELENIUM (Se)ADVANTAGE

Group 4

additive to glassreduce the transmission of sunlight in architectural glassmake pigments for ceramics, paint and plastics

useful in photocellssolar cells and photocopiers.convert AC electricity to DC electricity, so is extensively used in rectifiers.

SELENIUM (Se)DISADVANTAGE

Group 4

The Impact of Selenium Deficiency for the Body the symptoms arising from selenium deficiency, can be explained by the decrease in antioxidants in heart, liver and muscles, resulting in tissue death and organ failure.

Excess of selenium can cause very harmful effects that can result from consuming additional selenium overdose• queasiness and retch• hair and nail loss• neurological damage

TELLURIUM (Te)HISTORY

Group 4

Joseph Müller Von Reichenstein

Tellurium was discovered in the Habsburg Empire, in 1782 by Franz-Joseph Müller von Reichenstein in a mineral containing tellurium and gold. Martin Heinrich Klaproth named the new element in 1798 after the Latin word for "earth", tellus.

TELLURIUM (Te) Group 4PROPERTIES

atomic volume 20,5 Cm3/mol

Oxidation number 6, 4, 2, −2

Boiling point 1261 K (988 °C, 1810 °F)

Melting point 722.66 K (449.51 °C, 841.12 °F)

heat capacity 25.73 J/(mol·K)covalent radius 138±4 pmcrystal structure Hexagonal

Density (g cm−3) 6.24 g/cm3

Key isotopes 120, 122, 123, 124, 125, 126, 128, 130

electronegativity Pauling scale: 2.1

Energi of ionization 901,01 KJ/mol

Chemical reaction

TELLURIUM (Te) Group 4Tellurides Reduction of Te metal produces the tellurides and polytellurides

ZnTe + 2 HCl → ZnCl2 + H2Te

H2Te is unstable, whereas salts of its conjugate base [TeH]− are stable.

Halides

The +2 oxidation state is exhibited by the dihalides

Te + X2 + 2 X−→ TeX2-4

where X is Cl, Br, or I

Reaction of tellurium with airTellurium burns in air to form the solid dioxide tellurium(IV) oxide, TeO2.

Te(s) + O2(g) TeO2(s)

Chemical reaction

TELLURIUM (Te) Group 4

Reaction with water (H2O)

Tellurium dioxide reacts with water to form acid tellurous (H2TeO3).

TeO2 + H2O → H2TeO3

ALLOTROPES

TELLURIUM (Te) Group 4

Tellurium has two allotropes, crystalline and amorphous. When crystalline, tellurium is silvery-white and when it is in pure state it has

a metallic luster. It is a brittle and easily pulverized metalloid. Amorphous tellurium is a black-brown powder prepared by precipitating it from a solution of tellurous or telluric acid

(Te(OH)6).Tellurium is a semiconductor that shows a greater electrical conductivity in certain directions which depends on atomic alignment;

the conductivity increases slightly when exposed to light (photoconductivity). When in its molten state, tellurium is corrosive to copper, iron and stainless steel. Of the chalcogens, tellurium has the

highest melting and boiling points, at 722.66 K (841.12 °F) and 1,261 K (1,810 °F), respectively.

TELLURIUM (Te)

The principal source of tellurium is from anode sludges produced during the electrolytic refining of blister copper.The metal ions are reduced to the metals, while the telluride is converted to sodium tellurite.M2Te + O2 + Na2CO3 → Na2TeO3 + 2 M + CO2

Tellurites can be leached from the mixture with water and are normally present as hydrotellurites HTeO3

− in solutionThe hydrotellurites are converted into the insoluble tellurium dioxide while the selenites stay in solution.HTeO−3 + OH− + H2SO4 → TeO2 + SO2

−4 + 2 H2OThe reduction to the metal is done either by electrolysis or by reacting the tellurium dioxide with sulfur dioxide in sulfuric acid.[29]

TeO2 + 2 SO2 + 2H2O → Te + 2 SO2−4 + 4 H+

HOW TO OBTAIN!!

Group 4

ADVANTAGE

Group 4TELLURIUM (Te)

The largest consumer of tellurium is metallurgy, where it is used in iron, copper and lead alloysTellurium is used in cadmium telluride (CdTe) solar panels. Used to color ceramicsTellurite agar is used to identify members of the corynebacterium genus

The strong increase in optical refraction upon the addition of selenides and tellurides into glass is used in the production of glass fibers for telecommunicationsMixtures of selenium and tellurium are used with barium peroxide as oxidizer in the delay powder of electric blasting caps

DISADVANTAGE

Group 4TELLURIUM (Te)

Tellurium and tellurium compounds are considered to be mildly toxic and need to be handled with care, although acute poisoning is rare.[6Tellurium poisoning is particularly difficult to treat as many chelation agents used in the treatment of metal toxicities will increase the toxicity of tellurium. Tellurium is not reported to be carcinogenic.Humans exposed to as little as 0.01 mg/m3 or less in air exude a foul garlic-like odor known as "tellurium breath."[ This is caused from the tellurium being metabolized by the body, converting it from any oxidation state to dimethyl telluride, (CH3)2Te. This is a volatile compound with a highly pungent garlic-like smell. Even though the metabolic pathways of tellurium are not known, it is generally assumed that they resemble those of the more extensively studied selenium, because the final methylated metabolic products of the two elements are similar.

POLONIUM (Po)HISTORY

Group 4

MARIE AND PIERRE CURIE

lso tentatively called "radium F", polonium was discovered by Marie and Pierre Curie in

1898, and was named after Marie Curie's native land of Poland (Latin: Polonia). Poland at the time was under Russian, German, and Austro-Hungarian partition, and did not exist

as an independent country. It was Curie's hope that naming the element after her

native land would publicize its lack of independence. Polonium may be the first

element named to highlight a political controversy

POLONIUM (Po) Group 4PROPERTIES

atomic volume 22.70 cm3/mol

Oxidation number +4, +2and+6

Boiling point 963,03 °C

Melting point 527 K: 254 °C

heat capacity 20 W/mKAtomic radius

empirical: 168 pmcrystal structure monoclinic

Density (g cm−3) 9.3 g/cm3

Key isotopes 210Po, 214Po, and 218Po

electronegativity 2.0

ionization potential 8.42volts

POLONIUM (Po) Group 4Chemical reaction

ReactiontoAir

Polonium burned in the air and produce polonium(IV) dioxide

Po(s) +O2(g) PoO2(s)

Reactions withHalogenIn certain circum stances, polonium would react with chlorine, bromine and iodineto form tetrahalides.

Po(s) + 2Cl2(g) PoCl4(s)Po(s) + 2Br2(g) PoBr4(s)Po(s) + 2I2(g) PoI4(s)

Polonium is a radioactive element that exists in two metallic allotropes. The alpha form is the only known example of a simple cubic crystal structure in a single atom basis, with an edge length of 335.2 picometers; the beta form is rhombohedra. The structure of polonium has been characterized by X-ray

diffraction and electron diffraction.

POLONIUM (Po) Group 4ALLOTROPES

α-Po simple cubic

β –Po rhombohedra

POLONIUM (Po) Group 4HOW TO OBTAIN!!

Polonium is a very rare element in nature because of the short half-life of all its isotopes. 210Po, 214Po, and 218Po appear in the decay chain of

238U; thus polonium can be found in uranium ores at about 0.1 mg per metric ton (1 part in 1010), which is approximately 0.2% of the abundance of radium. The amounts in the Earth's crust are not harmful. Polonium has been found in tobacco smoke from tobacco leaves grown with phosphate fertilizers.Because it is present in such small concentrations, isolation of

polonium from natural sources is a very tedious process. The largest batch of the element ever extracted, performed in the first half of the 20th

century, contained only 40 Ci (1.5 TBq) (9 mg) of polonium-210 and was obtained by processing 37 tonnes of residues from radium production.[48]

Polonium is now obtained by irradiating bismuth with high-energy neutrons or protons.

ADVANTAGE

POLONIUM (Po) Group 4

Polonium Is used in nuclear testing with the release element beryllium neutron crate when shot alpha particles. In Printing and photography tools, polonium used in tools that ionize the air to eliminate electrostatic

current collection

DISADVANTAGE

POLONIUM (Po) Group 4

Polonium is highly dangerous and has no biological role.[17] By mass, polonium-210 is around 250,000 times more toxic than

hydrogen cyanide (the LD50 for 210Po is less than 1 microgram for an average adult (see below) compared with about 250 milligrams for hydrogen cyanide[66]). The main hazard is its

intense radioactivity (as an alpha emitter), which makes it very difficult to handle safely. Even in microgram amounts, handling

210Po is extremely dangerous, requiring specialized equipment (a negative pressure alpha glove box equipped with high

performance filters), adequate monitoring, and strict handling procedures to avoid any contamination.

IT IS JUST

UNUHEXIUM (Uuh)or LIVERMORIUM (Lv) Group 4

HISTORY

Joint Institute for Nuclear Research and Lawrence Livermore National Laboratory

Livermorium was first synthesized on July 19, 2000, when scientists at Dubna (JINR) bombarded a curium-248 target with accelerated calcium-48 ions. A single atom was detected, decaying by alpha emission with decay energy 10.54 MeV to an isotope of flerovium. The results were published in December 2000.

248Cm96 + 48Ca20 → 296 Lv*116 → 293Lv116 +3 1n0 → 289Fl114 + α

UNUHEXIUM (Uuh)or LIVERMORIUM (Lv) Group 4

PROPERTIESPhase solid (predicted)

Melting point 637–780 K (364–507 °C, 687–944 °F) (extrapolated)

Boiling point 1035–1135 K (762–862 °C, 1403–1583 °F) (extrapolated)

Density near r.t. 12.9 g/cm3 (predicted)

Heat of fusion 7.61 kJ/mol (extrapolated)

Heat of vaporization 42 kJ/mol (predicted)

Oxidation states −2, +2, +4 (predicted)

Ionization energies1st: 723.6 kJ/mol (predicted)[

2nd: 1331.5 kJ/mol (predicted)3rd: 2846.3 kJ/mol (predicted)

Atomic radius empirical: 183 pm (predicted)

Covalent radius 162–166 pm (extrapolated)

iso half-life

293Lv 61 ms

292Lv 18 ms

291Lv 18 ms

290Lv 7.1 ms

SUMMARY Group 4PROPERTIES

NATURE periodicity O S Se Te Po Lv

Atomic number 8 16 34 52 84 116

Element categoty nonmetallic

nonmetallic

nonmetallic

metalloids

metalloids

metal (probably)

Phase (25°c) Gases solid solid solid solid Predicted solid

Density (g/cm3) at 20 °c

0,001429 2,07 4,79 6,24 9,4 12.9 (predicted)

Melting point (°c) -218,4 115,21 217 449,5 254 364–507 (extrapolated)

Boiling point (°c) -182,7 444,6 684 989,9 962 762–862 (extrapolated)

elektronegetivitas 3,44 2,58 2,55 2,1 2,0 unknow