<small>[[Chemistry]] | [[19th Century]]</small> | | | | ----------------------------- | ---------------------------------------------------------------------------------------- | | Atomic Mass | [20.180 u](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Atomic-Weight) | | Standard State | [gas](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Physical-Description) | | Electron Configuration | [[He]2s22p6](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Electron-Configuration) | | Oxidation States | [0](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Oxidation-States) | | Atomic Radius (van der Waals) | [154 pm](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Atomic-Radius) | | Ionization Energy | [21.565 eV](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Ionization-Energy) | | Melting Point | [24.56 K](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Melting-Point) | | Boiling Point | [27.07 K](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Boiling-Point) | | Density | [0.0008999 g/cm³](https://pubchem.ncbi.nlm.nih.gov/element/10#section=Density) | | Year Discovered | [1898](https://pubchem.ncbi.nlm.nih.gov/element/10#section=History) |