The diameter of a rubidium atom is 495 pm We will consider two different ways of placing the atoms on a surface. In arrangement A, all the atoms are lined up with one another to form a square grid. Arrangement B is called a close-packed arrangement because the atoms sit in the 'depressions' formed by the previous row of atoms: (a) Using arrangement A, how many Rb atoms could be placed on a square surface that is 1.0 cm on a side?
Ch.2 - Atoms, Molecules, and Ions
Chapter 2, Problem 91a
(a) Assuming the dimensions of the nucleus and atom shown in Figure 2.10, what fraction of the volume of the atom is taken up by the nucleus?
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Atomic Structure
Atoms consist of a nucleus, which contains protons and neutrons, surrounded by electrons in various energy levels. The nucleus is significantly smaller than the entire atom, which includes the electron cloud. Understanding the relative sizes of these components is crucial for calculating volume fractions.
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Atom Structure
Volume Calculation
The volume of a sphere can be calculated using the formula V = (4/3)πr³, where r is the radius. To find the fraction of the atom's volume occupied by the nucleus, one must calculate the volumes of both the atom and the nucleus and then divide the nucleus's volume by the atom's volume.
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Constant-Volume Calorimetry
Fractional Volume
The fractional volume is a ratio that compares the volume of a part to the total volume. In this context, it is the volume of the nucleus divided by the volume of the atom, expressed as a decimal or percentage. This concept helps quantify how much space the nucleus occupies relative to the entire atom.
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Related Practice
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Textbook Question
(b) How many molecules of C13H18O2 are in this tablet?
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Textbook Question
Very small semiconductor crystals, composed of approximately
1000 to 10,000 atoms, are called quantum dots.
Quantum dots made of the semiconductor CdSe are now
being used in electronic reader and tablet displays because
they emit light efficiently and in multiple colors, depending
on dot size. The density of CdSe is 5.82 g/cm3.
(b) CdSe quantum dots that are 2.5 nm in diameter emit
blue light upon stimulation. Assuming that the dot is a
perfect sphere and that the empty space in the dot can
be neglected, calculate how many Cd atoms are in one
quantum dot of this size.
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Textbook Question
(b) Using the mass of the proton from Table 2.1 and assuming its diameter is 1.0 * 10-15 m, calculate the density of a proton in g>cm3.
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Textbook Question
Identify the element represented by each of the following symbols and give the number of protons and neutrons in each: (a) 7433X
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Textbook Question
Identify the element represented by each of the following symbols and give the number of protons and neutrons in each: (b) 12753X
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