Helium (He) Properties |
AHelium (AHe)
Properties 1/ |
Nuclear (2 protons/electrons)
- Atomic Number: 2
- Atomic Mass: 4.0026
- Atomic Energy: 0.00598 Ergs
- Group: 18 ; Period: 1
- Family: Noble Gases
- Bonding Radius: 0.93 Angstroms
- Atomic Radius: 0.49 Angstroms
- Atomic Volume: ? cm3mol-1
- 8
Isotopes: 3AHe to 10He
- Stable Isotopes: 3He,
4He
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Nuclear (2 Aprotons/positrons)
- Atomic Number:2
- Atomic Mass: 4.0026
- Atomic Energy: 0.00598 Ergs
- Group: 18 ; Period: 1
- Family: Noble Gases
- Bonding Radius: 0.93 Angstroms
- Atomic Radius: 0.49 Angstroms
- Atomic Volume: ? cm3mol-1
- 8 AIsotopes: 3AHe
to 10He
- Stable AIsotopes: 3AHe,
4AHe
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Physical
- Light, odorless, colorless, tasteless gas
- Density: 0.0001787 g cm-3
- Melting Point: -272 oC
( o K)
- Boiling Point: -268.6 oC
( o K)
- Specific Heat: 5.19 J g-1 K-1
- Heat of Vaporization: 0.0845 kJ mol-1
- Heat of Fusion: ? kJ mol-1
- Electrical Conductivity: ? 106 cm-1 Ohm-1
- Thermal Conductivity: 0.00152 W cm-1 K-1
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Physical
- Light, odorless, colorless, tasteless gas
- Density: 0.000179 g/cm-3
- Melting Point: -272 oC
( o K)
- Boiling Point: -268.6 oC
( o K)
- Specific Heat: 5.19 J g-1 K-1
- Heat of Vaporization: 0.0845 kJ mol-1
- Heat of Fusion: ? kJ mol-1
- Electrical Conductivity: ? 106 cm-1 Ohm-1
- Thermal Conductivity: 0.00152 W cm-1 K-1
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Chemical
- Valance Number: Zero
- Electron Configuration: 2
- Electronegativity: Zero
- 1st Ionization Potential: 24.6 Volts
- 2nd Ionization Potential: 54.4 Volts
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Chemical
- Valance Number: Zero
- Positron Configuration: 2
- Positronpositivity: Zero
- 1st Ionization Potential: 24.6 Volts
- 2nd Ionization Potential: 54.4 Volts
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Identified by Sir William Ramsey,
Nils Langet and P.T.Cleve,
Scotland and Sweden in 1895.
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Identified by Norm Hansen in 2001
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