Nobelium (element)
鍩 is a rare kanji used specifically for the chemical element nobelium. Its meaning is limited to that element name.
鍩 is a modern coined character for nobelium, combining the metal radical 金 with 若 for its sound value. The exact historical development is limited to its creation as a chemical element name.
The left side 金 (metal) tells you it's a metallic element, and the right side 若 (young) can remind you of the relatively recent discovery of nobelium. Together they point to a modern metal: nobelium.
For テン, imagine a scientist holding a tiny vial of nobelium and saying 'ten' as they count out ten atoms: ten -> テン, tying the sound to the metal.