Detection of urinary spermine by using silver-gold/silver chloride nanozymes.

See more Gold products. Gold (atomic symbol: Au, atomic number: 79) is a Block D, Group 11, Period 6 element with an atomic weight of 196.966569. The number of electrons in each of Gold's shells is 2, 8, 18, 32, 18, 1 and its electron configuration is [Xe]4f¹⁴² 5d¹⁰ 6s¹. The gold atom has a radius of 144 pm and a Van der Waals radius of 217 pm. Gold was first discovered by Early Man prior to 6000 B.C. In its elemental form, gold has a metallic yellow appearance. Gold is a soft metal and is usually alloyed to give it more strength. It is a good conductor of heat and electricity, and is unaffected by air and most reagents. It is one of the least reactive chemical elements. Gold is often found as a free element and with silver as a gold-silver alloy. Less commonly, it is found in minerals as gold compounds, usually with tellurium.

See more Silver products. Silver (atomic symbol: Ag, atomic number: 47) is a Block D, Group 11, Period 5 element with an atomic weight of 107.8682. The number of electrons in each of Silver's shells is 2, 8, 18, 18, 1 and its electron configuration is [Kr]4d¹⁰ 5s¹. The silver atom has a radius of 144 pm and a Van der Waals radius of 203 pm. Silver was first discovered by Early Man prior to 5000 BC. In its elemental form, silver has a brilliant white metallic luster. It is a little harder than gold and is very ductile and malleable, being exceeded only by gold and perhaps palladium. Pure silver has the highest electrical and thermal conductivity of all metals and possesses the lowest contact resistance. It is stable in pure air and water, but tarnishes when exposed to ozone, hydrogen sulfide, or air containing sulfur. It is found in copper, copper-nickel, lead, and lead-zinc ores, among others. Silver was named after the Anglo-Saxon word "seolfor" or "siolfur," meaning 'silver'.

Chlorine is a Block P, Group 17, Period 3 element. Its electron configuration is [Ne]3s²3p⁵. The chlorine atom has a covalent radius of 102±4 pm and its Van der Waals radius is 175 pm. In its elemental form, chlorine is a yellow-green gas. Chlorine is the second lightest halogen after fluorine. It has the third highest electronegativity and the highest electron affinity of all elements, making it a strong oxidizing agent. It is rarely found by itself in nature. Chlorine was discovered and first isolated by Carl Wilhelm Scheele in 1774. It was first recognized as an element by Humphry Davy in 1808.