Calculate the atomic radius in cm for the following: a. BCC metal with ao = 0.3226 nm. (Enter your answer to three significant figures.) r = cm b. FCC metal with ao = 4.3992 Å. (Enter your answer to three significant figures.) r = cm

Respuesta :

Explanation:

1) Edge length of the metal in BCC unit cell = [tex]a=0.33226 nm[/tex]

Atomic radius of the metal  atom = r

For BCC unit cell, relationship between edge length and radius is given as:

[tex]r=\frac{\sqrt{3}}{4}\times a=0.4330a[/tex]

[tex]r=0.4330\times 0.33226 nm=0.144 nm[/tex]

[tex]1 nm=10^{-7} cm[/tex]

[tex]r=0.144 nm=0.1439\times 10^{-7} cm=1.44\times 10^{-8} cm[\tex]

The atomic radius of the metal  atom in BCC unit cell is [tex]1.44 \times 10^{-8} cm[/tex].

2) Edge length of the metal in FCC unit cell = [tex]a=4.3992 \AA[/tex]

Atomic radius of the metal  atom = r

For FCC unit cell, relationship between edge length and radius is given as:

[tex]r=\frac{1}{2\sqrt{2}}\times a=0.3535a[/tex]

[tex]r=0.3535\times 4.3992 \AA=1.56 \AA[/tex]

[tex]1 \AA=10^{-8} cm[/tex]

[tex]1.56\AA=1.56 \times 10^{-8} cm[/tex]

The atomic radius of the metal  atom in FCC unit cell is [tex]1.56 \times 10^{-8} cm[/tex].