ヘリウム
2
He
族
18
周期
1
ブロック
s
陽子
電子
中性子
2
2
2
一般特性
原子番号
2
原子量
4.002602
質量数
4
カテゴリ
希ガス
色
無色
放射性
いいえ
名前の由来は、ギリシャ語の helios (太陽) からきた言葉です
結晶構造
面心立方格子
歴史
French astronomer Jules Janssen obtained the first evidence of helium during the solar eclipse of 1868.
Norman Lockyer and Edward Frankland suggested the name helium for the new element.
In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite.
It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet.
Norman Lockyer and Edward Frankland suggested the name helium for the new element.
In 1895, Sir William Ramsay discovered helium in the uranium mineral cleveite.
It was independently discovered in cleveite by Per Teodor Cleve and Abraham Langlet.
電子殻
2
電子配置
1s2
Unlike any other element, helium will remain liquid down to absolute zero at normal pressures
物理特性
相
気体
密度
0.0001785 g/㎝3
融点
0.95 K | -272.2 °C | -457.96 °F
沸点
4.22 K | -268.93 °C | -452.07 °F
融解熱
0.02 kJ/mol
蒸発熱
0.083 kJ/mol
熱容量
5.193 J/g·K
地殻中における存在比
5.5×10-7%
宇宙空間における存在比
23%
CAS登録番号
7440-59-7
PubChem CID番号
23987
原子特性
原子半径
31 pm
共有結合半径
28 pm
電気陰性度
-
イオン化エネルギー
24.5874 eV
モル体積
27.2 ㎝3/mol
熱伝導率
0.00152 W/㎝·K
酸化数
0
用途
Helium is used as a protective gas in growing silicon and germanium crystals, in titanium and zirconium production, and in gas chromatography.
Helium at low temperatures is used in cryogenics.
Helium is used for filling balloons and for pressurizing liquid fuel rockets.
Helium is used as a shielding gas in arc welding processes.
Helium at low temperatures is used in cryogenics.
Helium is used for filling balloons and for pressurizing liquid fuel rockets.
Helium is used as a shielding gas in arc welding processes.
Helium is not known to be toxic
同位体
安定同位体
3He, 4He不安定同位体
5He, 6He, 7He, 8He, 9He, 10He