Final answer:
A cell membrane is approximately 50 atoms thick, which is calculated by dividing the thickness of the membrane (around 7.5 to 10 nanometers) by the diameter of the atoms assumed to be twice the size of a hydrogen atom (0.2 nm).
Step-by-step explanation:
To estimate how many atoms thick a cell membrane is, assuming all atoms there average about twice the size of a hydrogen atom, we first need to know the thickness of the cell membrane and approximate size of the atoms. The general thickness of a cell membrane is around 7.5 to 10 nanometers (nm).
Given that a hydrogen atom has a diameter of approximately 0.1 nm, an atom twice the size would have a diameter of around 0.2 nm. Therefore, to calculate the number of atoms that would fit across the thickness of the membrane, we divide the thickness by the diameter of these larger atoms.
For example, if we use 10 nm as the membrane thickness and 0.2 nm as the average diameter of twice the size of a hydrogen atom, then:
10 nm / 0.2 nm = 50 atoms thick
Thus, a cell membrane is approximately 50 atoms thick, significantly less than any of the options provided (10^14, 10^16, 10^18, 10^20). None of the provided options are correct.