Calculate the radius of a copper atom. r =__________ pm
Hi simone! I am answering you from Italy. The question is really difficult to solve. My suggestion is as follows: Atomic weight of Copper = 63.55 g/mol Copper density = 8.97 g/cm^3 You can easily see that 8.97 grams of copper has a volume of 1 cm^3. You have to calculate the number of Cu mole which occupies 1 cm^3. That means: 8.97 g copper /63.55 g/mol = 0.1411487 mol in 1 cm^3 which means that 0.1411487 mol *6.022* 10^23 molecules/mol = 8.49997*10^+22 molecules of Copper in 1 cm^3. From these data you can calculate the volume per molecule =1 cm^3/8.49997*10^+22 molecules= =1.17647*10^-23 cm3/molecule You have to consider the molecule shape as a sphere. The volume of a sphere is given by: V= 4/3 pi*r^3 --> where pi = 3.14 so, 1.17647*10^-23 = 4/3 pi * r^3 --> r = 1.41091*10^-8 m = 141.091*10^-10 --> m = 141.091 Angstroms. Angstrom to picometer (A to pm) --> pm = 100 *A 141.091*100 Amstrongs = 1410.91 pm --> 'pm' is the abbreviation of picometer. Result: r = 1410.91 pm NOTE: 6.022* 10^23 molecules/mol is the value of the Avogadro constant [NA] which is defined as the ratio of the number of constituent particles [N] (atoms or molecules) in a sample to the amount of substance n (mole) through the relationship NA = N/n [Source: Wikipedia] Kind regards from Italy. C6H6
