This just a test to see if this website works!

1. Periodic Table Of The Elements
By: Ayah
Selenium

2. Selenium is a chemical element with symbol Se and atomic
number 34. It is a nonmetal with properties that are
intermediate between those of its periodic table column-
adjacent chalcogen elements sulfur and tellurium. It rarely
occurs in its elemental state in nature, or as pure ore
compounds. Selenium (Greek) Name: Selenium

3. Symbol: Se
• Atomic number: 34
• Atomic weight: 78.96 (3)
• Standard state: solid at 298 K
•CAS Registry ID: 7782-49-2
• Group in periodic table: 16
• Group name: Chalcogen
• Period in periodic table: 4
• Block in periodic table: p-block
• Color: grey, metallic lustre
•Classification: Non-metallic

4. Selenium has six naturally occurring
isotopes, five of which are stable: 74Se,
76Se, 77Se, 78Se, and 80Se. The last three
also occur as fission products, along with
79Se, which has a half-life of 327,000
years.[7][8] The final naturally occurring
isotope, 82Se, has a very long.

5. This is selenium. The Color: grey,
metallic luster, red,
black

6. Who found it?
Who found it? in nature, or as pure ore
compounds. Selenium (Greek σελήνη selene
smeaning "Moon") was discovered in 1817 by jons
Jacob Berzelius who noted the similarity of the new
element to the previously known tellurium
(named for the Earth).

7. Selenium is found impurely in metal sulfide ores, where it partially replaces
the sulfur. Commercially, selenium is produced as a byproduct in the refining
of these ores, most often during copper production. Minerals that are pure
selenide or selenate compounds are known, but are rare. The chief
commercial uses for selenium today are in glassmaking and in pigments.
Selenium is a semiconductor and is used in photocells.
Where can it be found?

8. Selenium salts are toxic in large amounts, but trace amounts are necessary
for cellular function in many organisms, including all animals. Selenium is a
component of the antioxidant enzymes glutathione peroxidase and
thioredoxin reductase (which indirectly reduce certain oxidized molecules in
animals and some plants). It is also found in three deiodinase enzymes, which
convert one thyroid hormone to another. Selenium requirements in plants
differ by species, with some plants requiring relatively large amounts, and
others apparently requiring none.
Did You Know?

9. Medical use!
The substance loosely called selenium sulfide (approximate formula SeS2) is
the active ingredient in some anti-dandruff shampoos.The selenium
compound kills the scalp fungus Malassezia, which causes shedding of dry
skin fragments. The ingredient is also used in body lotions to treat Tinea
versicolor due to infection by a different species of Malassezia fungus.

10. Controversial health effects
A number of correlative epidemiological studies have implicated selenium
deficiency (as measured by blood levels) in a number of serious or chronic
diseases, such as cancer, diabetes HIV/AIDS, and tuberculosis. In addition,
selenium supplementation has been found to be a chemopreventive for some
types of cancer in some types of rodents. However, in randomized, blinded,
controlled prospective trials in humans, selenium supplementation has not
succeeded in reducing the incidence of any disease, nor has a meta-analysis of
such selenium supplementation studies detected a decrease in overall mortality