Answer:
[tex]6.70\times 10^{-13}\ m[/tex]
Explanation:
Given:
Assumptions:
WE know that the radius of the [tex]n^{th}[/tex] orbit of an atom is given by:
[tex]r = \dfrac{n^2h^2}{4\pi^2kZe^2m}\\[/tex]
Let us find out the radius of the 1st orbit of the gold atom for which n = 1 and Z = 79.
[tex]r = \dfrac{n^2h^2}{4\pi^2kZe^2m}\\\Rightarrow r = \dfrac{(1)^2(6.62\times 10^{-34})^2}{4\pi^2\times 9\times 10^9\times 79\times (1.6\times 10^{-19})^2\times 9.1\times 10^{-31}}\\\Rightarrow r =6.70\times 10^{-13}\ m[/tex]