Question

The radius of an atom of rubidium (Rb) is about 2.1 Å. (a) Express this distance in nanometers (nm). Express this distance in picometers (pm). pm (b) How many rubidium (Rb) atoms would have to be lined up to span 1.0 mm? (c) If the atom is assumed to be a sphere, what is the volume in cm3 of a single rubidium (Rb) atom?

Answer 1

Radius of Rubidium (R6) atom = 2.16 la) We know that WE LAO = 10-8 cm =10 lom & luma 107cm = 109m .:1A = 10lom - 10 x 10 9 Inm 10 Inmalot : Inma 10 A xol? 2140 2.14° Totox nm - 0.21 nm = 2.1810 nm

(3) 1pm - 10-12m 10 10 x 102mm - 10-2 A la = 100pm 2:14° = ? 2.1A x 100pm - TAO ~ 210pm No. of Rb atoms in Imm: (6) Radius of 1 Rb atom = 2.1810-8 cm 1cm = lomme 2. 14108 cm a? = 2.1x107mm latom occupies 2018 107mm 1 mm mm xl alom to = 2.1X16-7 47, 61,904 . 7 atom 47, 61,905 atomy -
c)

Volume of the sphere = 4πr³/3

Given that radius of Rb atom = 2.1×10^-8 cm

  

4* 22 * (2.1 * 108cm) 7 * 3

= 38.808×10^-24 cm^{​​​​​3}

=3.881×10^-23 cm^{​​​​​3}