Answer:
1.0 × 10⁸ ruthenium atoms
Explanation:
Step 1: Calculate the diameter (d) of an atom of ruthenium
The diameter of an atom is twice its radius.
d = 2 × r = 2 x 178 pm = 356 pm
Step 2: Convert "d" to meters
We will use the conversion factor 1 m = 10¹² pm.
356 pm × 1 m/10¹² pm = 3.56 × 10⁻¹⁰ m
Step 3: Convert the distance of the tip of a finger (D) to meters
We will use the conversion factor 1 m = 10² cm.
3.6 cm × 1 m/10² cm = 0.036 m
Step 4: Calculate the number of atoms of ruthenium required
We will use the following expression.
D/d = 0.036 m/3.56 × 10⁻¹⁰ m = 1.0 × 10⁸