Final answer:
The size of an atom is approximately 10^-10 meters, which is also known as an ångström, a commonly used unit for measuring atomic and molecular dimensions. (option d)
Step-by-step explanation:
The size of an atom is on the order of 10-10 meters (m). This measurement corresponds to the diameter of the atom's electron cloud, which is vastly greater than the size of the nucleus within it. When considering atoms, the unit often used to express their size is the ångström (Å), which is equivalent to 10-10 meters. This unit provides a convenient scale for describing atomic and molecular structures.
Based on the options provided in the question and the reference to ångströms, the correct answer to the question 'Which of the following represents the size of an atom?' is (d) 10-10 meters.
Hence, the answer is option d