Answer:
A is the answer. Hope this helped.
<u>Answer:</u>
<u>For a:</u> The edge length of the unit cell is 314 pm
<u>For b:</u> The radius of the molybdenum atom is 135.9 pm
<u>Explanation:</u>
To calculate the edge length for given density of metal, we use the equation:
where,
= density = 
Z = number of atom in unit cell = 2 (BCC)
M = atomic mass of metal (molybdenum) = 95.94 g/mol
= Avogadro's number = 
a = edge length of unit cell =?
Putting values in above equation, we get:
![10.28=\frac{2\times 95.94}{6.022\times 10^{23}\times (a)^3}\\\\a^3=\frac{2\times 95.94}{6.022\times 10^{23}\times 10.28}=3.099\times 10^{-23}\\\\a=\sqrt[3]{3.099\times 10^{-23}}=3.14\times 10^{-8}cm=314pm](https://tex.z-dn.net/?f=10.28%3D%5Cfrac%7B2%5Ctimes%2095.94%7D%7B6.022%5Ctimes%2010%5E%7B23%7D%5Ctimes%20%28a%29%5E3%7D%5C%5C%5C%5Ca%5E3%3D%5Cfrac%7B2%5Ctimes%2095.94%7D%7B6.022%5Ctimes%2010%5E%7B23%7D%5Ctimes%2010.28%7D%3D3.099%5Ctimes%2010%5E%7B-23%7D%5C%5C%5C%5Ca%3D%5Csqrt%5B3%5D%7B3.099%5Ctimes%2010%5E%7B-23%7D%7D%3D3.14%5Ctimes%2010%5E%7B-8%7Dcm%3D314pm)
Conversion factor used: 
Hence, the edge length of the unit cell is 314 pm
To calculate the edge length, we use the relation between the radius and edge length for BCC lattice:
where,
R = radius of the lattice = ?
a = edge length = 314 pm
Putting values in above equation, we get:
Hence, the radius of the molybdenum atom is 135.9 pm
Answer:
Magnesium and calcium belong to the second group i. e. alkaline earth metals. They are known as earth metals because they are extracted from the earth. They are very reactive elements. Their reactivity increases when we go from top to bottom because the outermost electrons goes farther from the nucleus i. e. atomic radius increases so less energy is needed for its removal.
Answer:
D. As white light passes through a prism , it bends and separates into different colors
Explanation:
When light enters a prism, it experiences a phenomenon called 'refraction'.
Refraction occurs when light crosses the interface between two mediums with different optical density; when this happens, the light bends and also changes speed.
The angle at which the ray of light is refracted into the second medium depends on the optical density of the two mediums, but also on the wavelength of the light.
In particular, longer wavelengths (red color) are refracted the least, while shorter wavelengths (violet color) are refracted the most.
As a result, when white light (consisting of all the colors of visible light) enters into a prism, they different wavelengths are separated: therefore, white light separates into different colors.
So, the correct answer is
D. As white light passes through a prism , it bends and separates into different colors
