|Atomic Symbol||Atomic symbol::Tc|
|Atomic Number||Atomic number::43|
|Atomic Weight||Atomic weight::98 g/mol|
|Chemical series||Transition Metals|
|Appearance|| silvery grey metal |
|Group, Period, Block||7, 5, d|
|Electron configuration||[Kr] 5s2 4d5|
|Electrons per shell|| 2, 8, 18, 13, 2 |
|CAS number||CAS number::7440-26-8|
|Melting point||Melting point::2474K|
|Boiling point||Boiling point::5150K|
|Isotopes of Technetium|
|All properties are for STP unless otherwise stated.|
Technetium is a transition metal belonging to group 5, 7a. Element symbol is Tc, and it's atomic weight is 98g/mol. Melting point is 2157℃, and boiling point 4265℃. Density is 11g/cm3 and liquid range is 2108K. Superconduction temperature of technetium is 7.8K.  The color of Technetium is silver grey, and they loses it's gloss in humid space. Chemical properties of technetium are similar to rhenium. 
Technetium has twenty-two reported isotopes with masses ranging from 90 to 111. All the isotopes of technetium are radioactive. Technetium is the first of artificial radioactive elements, and 19 kinds of known radio nuclides ranging in mass number 92-105. It has a short half-life except 99Tc · 97Tc · 98Tc. The most useful isotope of technetium is 99Tcm. It is used in many medical isotope experiment. 
The most stable isotopes are technetium-97, technetium-98, and technetium-99. They have half lives of more than a million years. Isotopes are two or more forms of an element. Isotopes are different from each other. We can find this fact from their mass number. The mass number is the number which is written on the right of the element's name. The mass number represents the number of protons and neutrons in the nucleus of an atom of the element. The number of protons determines the element. But the number of neutrons in the atom of any one element can be different. Each variation is an isotope. Technetium has never been found on Earth. It has been detected in some stars. It can be detected by analyzing the light produced by the stars. 
Technetium is Widely used in diagnostic nuclear medicine. 99Tc is used as a beta-particle source which does not produce gamma rays. The gamma rays can be used as a gamma camera. Technetium is also used for electric corrosion inhibitors of steel and acid ion.  Technetium-99m is used in 80 to 90 percent of all diagnostic procedures that use radioactive elements, and it also has a very long half life. Technetium-95 is used as a radioactive tracer.  5 ppm of KTcO4 is able to protect mild carbon steels in aerated distilled water at temperatures up to 250°C limited to closed systems, because technetium is radioactive. 
Technetium was discovered by Carlo Perrier, Emilio Segre in 1937 in Italy. Technetium was predicted on the basis of the periodic table by Mendeleev. Mendeleev suggested that it should be very similar to manganese. So he said that it should be named 'ekamanganese'. Technetium was reported that it was discovered in 1925, the time when it was named masuranium. Actually, the element was discovered by C. Perrier and Emilio Gino Segre in 1937, Italy. Technetium was the first element to be produced artificially.Their isotopes are all radioactive. It is named after the Greek technetos, meaning artificial. 
Basic information about Technetium.
- G. W. C. Kaye, T. H. Laby. Technetium Royal-Society-of-Chemistry. Web. Date of access: 9 October 2014.
- . Facts-about-technetium Live-Science. Web. date of publication: November 20, 2013 author unknown.
- chemical-properties-of-technetium Lenntech B.V. Web. Date unknown. author unknown
- Mark Winter Chemistryexplained. Web. Date unknown.
- . technetium. 네이버블로그. Web. Accessed: November 03, 2005.난니가행복했으면좋겠어
- . technetium-element-facts. chemicool. Web. Accessed: October 18, 2012. author unknown.
- . technetium:uses. webelements. Web. accessed date unknown. Mark Winter.
- Technetium technetiumtheessential. Web. Date unknown. Author Unknown.