#### • Class 11 Physics Demo

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Atomic nucleus - Wikipedia, the free encyclopedia

The nucleus of an atom consists of protons and neutrons (two types of ...

Answers:Hi Stuart, The Bohr radius of an atom is: a0 = Bohr radius = 0.53 Angstrom = 5.3 x 10^-11 m The radius of a typical nucleus is r = radius of typical nucleus = 10^-15 m So, r / a0 = 10^-15 / 5.3x10^-11 = 1.88 x 10^-5 So that's how you get the ratio to be ~10^-5. http://en.wikipedia.org/wiki/Nuclear_radius http://en.wikipedia.org/wiki/Bohr_radius That's your answer! ANagah.

Question:Carbon-12 contains 6 protons and 6 neutrons. The radius of the nucleus is approximately 2.7 fm, and the radius of the atom is approximately 70 pm. Calculate the volume of the nucleus and the volume of the atom. V nucleus= V atom= What percentage of the carbon atom's volume is occupied by the nucleus? Vnucleus/Vatom=

Answers:Estimate the volume to be approximated by the shape of a sphere: V = (4/3)(pi)(r^3) V(nucleus) = (4/3)(pi)(2.7x10^-3 pm)^3 = 8.2x10^-5 pm^3 V(atom) = (4/3)(pi)(70 pm)^3 = 2.0x10^4 pm^3 The percentage of the volume of the atom occupied by the nucleus is: [V(nucleus)/V(atom)]x100% [(8.2x10^-5 pm^3)/(2.0x10^4 pm^3)] x 100% = (4.1x10^-7) % That's virtually no space at all! Thinking about it is just mind-blowing.

Question:Why is the radius of a neutral metal atom always larger than the radius of a positive ion? A. The nucleus repels the remaining electrons. B. The positive ion has lost its outer level. C. The atomic orbitals contract all by themselves. D. The number of principal energy levels is always increased. E. The metal's outer level is completely filled.