General: |
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Name: Helium
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Symbol: He
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Group: Noble Gas
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Atomic weight: 4.00260
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Density @ 293 K: 0.0001787 g/cm3
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Atomic volume: ?
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Group: Noble Gas
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discovered: 1895
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States: |
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state (s, l, g): g
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melting point: K
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boiling point: 4.2 K
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Heat of fusion: ?
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Heat of vaporization: 0.0845 kJ/mol
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Energies: |
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1st ionization energy: 2372.3 kJ/mole
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electronegativity:
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2nd ionization energy: 5250.3 kJ/mole
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electron affinity: 0 kJ/mole
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3rd ionization energy: kJ/mole
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Specific heat: 5.193 J/gK
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heat atomization: 0 kJ/mole atoms
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Oxidation & Electrons: |
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Shells: 2
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electron configuration: 1s2
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minimum oxidation number: 0
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maximum oxidation number: 0
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min. common oxidation no.: 0
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max. common oxidation no.: 0
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Appearance & Characteristics: |
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structure:
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color: colorless
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uses: cryogenics, blimps
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toxicity: no
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hardness: mohs
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characteristics: Inert, dens
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Reactions: |
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reaction with air: none
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reaction with 6M HCl: none
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reaction with 6M HCl: none
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reaction with 15M HNO3: none
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reaction with 6M NaOH: none
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Other Forms: |
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number of isotopes: 2
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hydride(s): none
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oxide(s): none
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chloride(s): none
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Radius: |
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ionic radius (2- ion): pm
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ionic radius (1- ion): pm
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atomic radius: 31 pm
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ionic radius (1+ ion): pm
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ionic radius (2+ ion): pm
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ionic radius (3+ ion): pm
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Conductivity: |
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thermal conductivity: 0.15 J/m-sec-deg
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electrical conductivity: 1/mohm-cm
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polarizability: 0.198 A^3
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Abundance: |
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source: Natural gas, air
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rel. abund. solar system: 9.435 log
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abundance earth's crust: -2.1 log
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cost, pure: 5.2 $/100g
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cost, bulk: $/100g
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