text: The first self-assembling monolayers were formed by alkane-thiols bonding to this metal.
full_question: The first self-assembling monolayers were formed by alkane-thiols bonding to this metal. Colloidal particles of this element are used to stain in electron microscopy. A cross-section proportional to the fourth power of the cosecant was first proposed for elastic scattering off this element. This metal has +1 and +3 oxidation states. This metal does not dissolve in nitric acid, but does (*) dissolve in a 1:3 mixture of nitric and hydrochloric acids. This element was described as a piece of tissue paper, deflecting a cannonball, into a ring of zinc sulfide, during the experiment which discovered the nucleus. It is the most malleable and ductile metal. For 10 points, name this element with symbol Au.
first_sentence: The first self-assembling monolayers were formed by alkane-thiols bonding to this metal.
raw_answer: gold [or Au until it is read]