He
Helium is a Noble Gases element with the symbol He and atomic number 2. Located in period 1, group 18 (s-block), it has an atomic weight of 4.0026 u and is classified as a gas at standard temperature and pressure. First identified in 1868 by Pierre Janssen in France. Helium has an electron configuration of 1s² with 1 electron shells containing 2 electrons respectively. It is commonly used in: balloons, cooling mri magnets, welding shield gas.
氦是一种稀有气体元素，符号为He，原子序数为2。位于第1周期，第18族（s区），原子量为4.0026 u，在标准温度和压力下为气体。于1868 年首次被确认，由Pierre Janssen发现。氦的电子排布为1s²，具有1个电子层，分别含有2个电子。常见用途包括：气球，冷却MRI磁体，焊接保护气。
Basic Properties基本属性
- Atomic Number原子序数
- 2
- Atomic Weight原子量
- 4.0026 u
- Category分类
- Noble Gases稀有气体
- State at STP标准状态
- Gas气体
- Period周期
- 1
- Group族
- 18
- Block区
- s-blocks区
Physical Properties物理性质
- Melting Point熔点
- —
- Boiling Point沸点
- -268.93°C
- Density密度
- 0.0001785 g/cm³
- Crystal Structure晶体结构
- Hexagonal六方晶系
- Atomic Radius原子半径
- 31 pm
- Ionic Radius离子半径
- —
- Electronegativity电负性
- —
Electron Configuration电子排布
- Config电子构型
- 1s²
- Shells电子层
- 2
- Oxidation States氧化态
- 0
Electron Shells电子层结构
Discovery发现历史
- Year年份
- 18681868 年
- Discoverer发现者
- Pierre Janssen
- Country国家
- France法国
Uses & Applications用途
Balloons, cooling MRI magnets, welding shield gas
气球，冷却MRI磁体，焊接保护气
Common Compounds常见化合物
—
—
Room Temperature常温特性
colorless gas
无色气体
Did You Know? 你知道吗？
The name Helium comes from He and it was first identified in 1868.
氦的名称来源于其符号He，于1868年首次被确认。
Memory Aid记忆口诀
Helium makes balloons float high
氦气让气球飞起来
Appearance外观
colorless gas
无色气体
Safety Information安全须知
- Generally inert and non-toxic. Asphyxiation risk only in confined spaces at high concentrations.
- 通常为惰性无毒气体。仅在密闭空间高浓度时有窒息风险。