2 He Helium 4,0026 u

Helium

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Periyot
1
Grup
18
Blok
s-Blok
Faz (STP)
Gas

Helium is the second lightest and second most abundant element in the universe. It is an inert noble gas used in cryogenics and as a lifting gas.

Görünüm: Colorless gas

About Helium

Chemically inert and second only to hydrogen in lightness, helium fills atomic number 2 with an atomic mass of 4.0026. Its two electrons complete the 1s shell, a closed configuration reflected in an exceptionally high ionization energy of 2372 kJ/mol and the absence of ordinary chemistry. The colorless noble gas remains liquid closer to absolute zero than any other substance, boiling at just 4.2 K. Pierre Janssen first detected it in 1868, in the spectrum of the Sun rather than on Earth. As the second most abundant element in the universe, helium is valued in cryogenics, where its low boiling point is essential, and as a non-flammable lifting gas—both uses resting on the stability that keeps it from bonding. It sits in group 18.

Fiziksel Özellikler

Atom Kütlesi 4.0026 u
Yoğunluk 0.0001785 g/cm³
Erime Noktası -272.2 °C
Kaynama Noktası -268.9 °C
STP'de Faz Gas
Atom Yarıçapı 31.0 pm

Elektronik Özellikler

İyonlaşma Enerjisi 2372.3 eV
Değer Elektronları 2

Elektron Yapısı

Yapılandırma 1s²

Electron Shell Configuration

Helium electron shell configuration He 2e⁻
Electron shell structure of Helium — electrons per shell.
Shell Electrons
1 (K) 2

Position in Periodic Table

Helium position in the periodic table He

Keşif

Keşfeden: Pierre Janssen
Yıl: 1868

Blok ve Periyot

Blok

s p d f

Periyot

1 2 3 4 5 6 7

Periyodik Tablo

Lantanitler Aktinitler

He İçeren Reaksiyonlar

Proton-Proton Chain (Solar Fusion)

4¹H → ⁴He + 2e⁺ + 2νₑ + energy

Nuclear

Deuterium-Tritium Fusion

²H + ³H → ⁴He + ¹n

Nuclear

Alpha Decay of Radium-226

²²⁶Ra → ²²²Rn + ⁴He

Nuclear

Alpha Decay of Polonium-210

²¹⁰Po → ²⁰⁶Pb + ⁴He

Nuclear

Alpha Decay of Uranium-238

²³⁸U → ²³⁴Th + ⁴He

Nuclear
Tüm 12 reaksiyonu gör →

Daha fazla Soy Gaz

10 Ne Neon 18 Ar Argon 36 Kr Krypton 54 Xe Xenon 86 Rn Radon

Explore on Science FYI

StarFYI
Sun (Sol)

Helium produced by hydrogen fusion in stellar cores

Frequently Asked Questions

What is Helium?
Helium (He) is a chemical element with atomic number 2. It is a gas at standard temperature and pressure, classified as a soy gaz.
What are the key properties of Helium?
Helium has an atomic mass of 4.0026 u, density of 0.0001785 g/cm³, melting point of -272.2°C, boiling point of -268.9°C.
What is the electron configuration of Helium?
The electron configuration of Helium is 1s2. It is in the s-block of the periodic table.
Who discovered Helium?
Helium was discovered by Pierre Janssen in 1868.