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Gold (Au) has a density of 19.3 g/cm^3 and forms a face centered cubic crystal structure. Calculate the radius a gold atom.

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Final answer:

To calculate the radius of a gold atom in a face-centered cubic crystal structure, you can use the formula: Edge length (a) = (4r)/√2. By rearranging the formula and substituting the given values, you can find that the radius of a gold atom is approximately 0.707 cm.

Step-by-step explanation:

Gold has a face-centered cubic (FCC) crystal structure, which means that the atoms are arranged in a cubic formation with atoms at each corner and in the center of each face.

To calculate the radius of a gold atom, we can use the formula:

Edge length (a) = (4r)/√2

Density (d) = Mass (m)/Volume (V)

= 19.3 g/cm³

Using the density equation, we can rearrange it to find the volume of the unit cell:

Volume (V) = Mass (m)/Density (d)

= 1 cm³

From the formula of FCC structure, we know that there are 4 atoms per unit cell.

So the volume of a gold atom can be expressed as:

Volume of atom = Volume of unit cell / 4

= 1 cm³ / 4

Now, we can calculate the radius (r) using the formula:

Radius (r) = (√2) * (Edge length (a))/4

= (√2) * (4r)/√2)/4

= r

Thus, the radius of a gold atom is equal to its edge length (a).

Therefore, we have:

Edge length (a) = (√2) * radius (r)

Let's substitute the value of the edge length (a) as 1 cm into the equation:

(√2) * radius (r) = 1 cm

radius (r) = 1 cm / (√2)

= 0.707 cm.

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