Selenium

34
Se
Golongan
16
Periode
4
Blok
p
Proton
Elektron
Neutron
34
34
45
Sifat Umum
Nomor atom
34
Massa atom
78,96
Nomor massa
79
Kategori
Nonlogam lainnya
Warna
Abu-abu
Radioaktif
Tidak
From the Greek word Selene, moon
Struktur kristal
Monoklinik Sederhana
Sejarah
Selenium was first observed in about the year 1300 by the alchemist Arnold of Villanova.

Selenium was discovered in 1817 by Jöns Jacob Berzelius and Johan Gottlieb Gahn who noted the similarity of the new element to the previously-known tellurium.

In 1873, Willoughby Smith found that the electrical resistance of grey selenium was dependent on the ambient light.
Elektron per kulit
2, 8, 18, 6
Konfigurasi elektron
[Ar] 3d10 4s2 4p4
Se
Selenium deficiency in animals can lead to slow growth
Sifat Fisika
Fase
Solid
Kepadatan
4,809 g/cm3
Titik lebur
494,15 K | 221 °C | 429,8 °F
Titik didih
958,15 K | 685 °C | 1265 °F
Kalor peleburan
5,4 kJ/mol
Kalor penguapan
26 kJ/mol
Kapasitas kalor molar
0,321 J/g·K
Kelimpahan di kerak bumi
5×10-6%
Kelimpahan di alam semesta
3×10-6%
Ultrapure
Kredit Gambar: Images-of-elements
Ultrapure black, amorphous selenium
Nomor CAS
7782-49-2
PubChem CID Number
6326970
Sifat Atom
Jari-jari atom
120 pm
Jari-jari kovalen
120 pm
Elektronegativitas
2,55 (Skala Pauling)
Potensi Ionisasi
9,7524 eV
Volume atom
16,45 cm3/mol
Kondusivitas termal
0,0204 W/cm·K
Bilangan oksidasi
-2, 2, 4, 6
Aplikasi
Selenium is used in the glass industry to decolorize glass and to make red-colored glasses and enamels.

It is used as a catalyst in many chemical reactions.

It is also used as a photographic toner, and as an additive to stainless steel.

Selenium sulfide is used in anti-dandruff shampoos.
Many of selenium's compounds, such as selenates and selenites, are highly toxic
Isotop
Isotop stabil
74Se, 76Se, 77Se, 78Se, 80Se
Isotop tidak stabil
65Se, 66Se, 67Se, 68Se, 69Se, 70Se, 71Se, 72Se, 73Se, 75Se, 79Se, 81Se, 82Se, 83Se, 84Se, 85Se, 86Se, 87Se, 88Se, 89Se, 90Se, 91Se, 92Se, 93Se, 94Se