Roughly speaking, the radius of an atom is about  10,000 times greater than that of its nucleus. If an atom were magnified so that the radius of its nucleus  became 2.0 cm, about the size of a marble, what would  be the radius of the atom in miles? (1 mi 5 1609 m.)

3. Which of the following statements about atomic properties is TRUE? (a) The magnitude of the electron affinity of fluorine is greater than that of carbon. (b) The atomic radius of boron is greater than that of beryllium. (c) The radius of Sit is greater than that of aluminum. (d) The ionic radius of Cr is larger than that of t. (e) Energy is always released when an atom in the gas phase loses an electron.

Helium is the lightest noble gas and the second most abundantelement (after hydrogen) in the universe.

a. The radius of a helium atom is 3.1 x 10^-11 m; the radius ofits nucleus is 2.5 x10^-15 m. What fraction of the spherical atomicvolume is occupied by the nucleus?

b. The mass of a helium-4 atom is 6.64648 x 10^-28 g. Whatfraction of this atom's mass is contributed by itsnucleus?

107. Carbon-12 contains six protons and six neutrons. The radius of the nucleus is approximately 2.7 fm (femtometers) and the ra- dius of the atom is approximately 70 pm (picometers). Calcu. late the volume of the nucleus and the volume of the atom. What percentage of the carbon atom's volume is occupied by the nucleus? (Assume two significant figures.)