A silver atom has 47 electrons around its nucleus. There are 2 in the K shell, 8 in the L shell, 18 in the M shell, 18 in the N shell and 1 in the O shell.
Silver loses the single electron in its outer O shell to become a singly charged positive ion, \mathrm{Ag}^{+}.
Silver is in group 11, like copper, and it forms ions even less readily than copper; it does not dissolve in hydrochloric acid or dilute sulfuric acid, but it does dissolve in nitric acid.
When a solution containing chloride ions, \mathrm{Cl}^{-}, is added to a solution of silver nitrate, \mathrm{AgNO_3}, white silver chloride, \mathrm{AgCl}, is precipitated.
\mathrm{Ag}^{+} + \mathrm{Cl}^{-} \longrightarrow \mathrm{AgCl}
This reaction is used to test whether a solution contains chloride ions.
With bromide ions, pale yellow silver bromide, \mathrm{AgBr}, is precipitated, and with iodide ions, yellow silver iodide, \mathrm{AgI}.
When light falls on silver chloride or silver bromide, it decomposes into tiny grains of silver, and the compound turns dark.
2\mathrm{AgBr} \longrightarrow 2\mathrm{Ag} + \mathrm{Br_2}
This property has long been used in photography with film. Silver compounds such as silver nitrate are stored in brown bottles to keep light out.
Ammonia solution is added to silver nitrate solution to make ammoniacal silver nitrate solution, and an aldehyde is added to it and the mixture is warmed. Silver is then deposited on the inside of the test tube, which becomes a mirror.
This is called the silver mirror reaction. It happens because the aldehyde reduces the silver ions, so that silver comes out of the solution.
Mirrors are made by coating the back of glass with a thin film of a metal such as silver or aluminium.
Silver reacts with the tiny amount of hydrogen sulfide in the air, and black silver sulfide, \mathrm{Ag_2S}, forms on its surface, so silver gradually tarnishes.
Of all metals, silver is the best conductor of electricity and heat, and it also reflects light the best. Because it is expensive, copper is used for electric wires, but silver is used for the contacts of electronic parts, tableware, jewellery and more.
Silver ions can stop bacteria from multiplying, so they are also used in antibacterial treatments.