Answer:- [tex]2.40*10^1^0atoms[/tex]
Solution:- It is a simple unit conversion problem. We could solve this using dimensional analysis.
We know that, 1 US dollar = 100 cents
1 cent = 1 US penny
So, 1 US dollar = 100 US pennies
[tex]1g=10^6\mu g[/tex]
Let's make the set up starting with 1 penny as:
[tex]1penny(\frac{$1}{100pennies})(\frac{1\mu g}{$1000})(\frac{1g}{10^6\mu g})(\frac{6.02*10^2^3atoms}{251g})[/tex]
= [tex]2.40*10^1^0atoms[/tex]
Therefore, we can bye [tex]2.40*10^1^0atoms[/tex] of Cf in one US penny.