Question

The smallest
atom known is hydrogen, with each atom being
represented as a sphere having a diameter of
0.000 000 07 mm (or 7 × 10−8 mm) (Table 2.3).
Atoms of different elements have different diameters
as well as different masses. How many atoms of
hydrogen would have to be placed side by side
along the edge of your ruler to fill just one of the 1 mm division

Answer 1

$C=2πr$

$=2×22/7×0.00000007$

$=0.00000022mm$

1 atom =0.00000022mm

2 atoms of =?

$=2×0.00000022mm$

$=0.00000044mm$

2 atoms of Hydrogen= 0.00000044mm

?= 1mm

$=2/0.00000044mm$

$=4,545,454$ atoms of Hydrogen