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Atomic Structure - Cont.
Atomic Size
Measuring the size of an atom is not a straightforward task. One difficulty is that an atom does not have a clear boundary showing its outer edge. We often use hard spheres with defined edges to represent atoms in our models, and these models serve to represent atoms for many of our purposes. However, hard spheres do not accurately represent the boundaries of real atoms.
Another difficulty in measuring atomic size is that atoms are so tiny. Until recently, scientists were not able to measure their sizes directly. Instead, they have estimated their sizes using different methods and data.
One method involves measuring the distance between two atoms associated in a solid. The solid is measured on all sides to determine its length, height, and width. The number of atoms in the solid is determined as well by dividing the mass of the solid by the mass of a single atom. Using these pieces of information, numerical values can be calculated for the distance between two atomic nuclei. This distance is the atomic diameter. The atomic radius is half of the atomic diameter. Figure 10 shows these relationships between atoms in a solid.
Advances in microscopy are currently allowing scientists to take pictures of individual atoms. These pictures confirm that the diameter of an atom is approximately 1 × 10−10 m. For such small dimensions, a unit of length called the angstrom is used. 1 Å = 1 × 10−10 m, so atoms are about 1 Å in size. This is a rough estimation of size, since atoms of different elements have different diameters.
Which of the following statements is/are true about the diameter of an atom?
The diameter of an atom is given as an exact value.
An atom does not have a clear boundary showing its outer edge.
Atoms are so tiny to be measured directly.
The diameter of an atom is considered to be an estimate value.
Which of the following statements is/are true about the diameter of an atom?
The diameter of an atom is considered to be an estimate value.
The diameter of an atom is given as an exact value.
An atom does not have a clear boundary showing its outer edge.
