Which of the following statements are correct: A. In SC structure $a =2r$ B. In SC structure $a =r/2$ C. In BCC structure $a = 4r/\sqrt{3}$. D. In FCC structure $a = 2\sqrt{2} r$ Where $a$ is a lattice parameter and $r$ is the atomic radius.
To determine which of the statements about the cubic structures are correct, we need to evaluate each statement based on the geometry of the crystal lattice structures.
- Simple Cubic (SC) Structure: In a Simple Cubic structure, each corner atom touches its adjacent corner atoms. The lattice parameter a relates to the atomic radius r as follows:
- a = 2r. This is because atoms at corners are spaced apart by twice the atomic radius to touch each other.
- Body-Centered Cubic (BCC) Structure: In a BCC structure, the atoms touch along the body diagonal. The length of the body diagonal is \sqrt{3}a, which contains 4 atomic radii. Hence, the relation is:
- a = \frac{4r}{\sqrt{3}}.
- Face-Centered Cubic (FCC) Structure: In an FCC structure, the atoms touch along the face diagonal, with the face diagonal being \sqrt{2}a, containing 4 atomic radii. Thus:
- a = 2\sqrt{2}r.
- Incorrect Statement for Simple Cubic: Statement B claims a = \frac{r}{2}, which is incorrect for the Simple Cubic structure as demonstrated above.
To summarize, the correct answer for the given set of statements is: A, C, and D.
Important Questions from Chemistry (CUET PG) Mixed
- Which of the following atmospheric gas does not dissolve in water at standard temperature and pressure conditions?
- Which of the following physical processes is responsible for the blue color of the sky?
- Arrange the following coal types in the increasing order of their heat content (KJ/kg)
(A). Peat
(B). Lignite
(C). Anthracite
(D). Bituminous
(E) Sub-bituminous
Choose the correct answer from the options given below: - In which of the following layers of atmosphere, does the temperature decrease with the increase in height from the earth's surafce?
(A). Troposphere
(B). Mesosphere
(C). Thermosphere
(D). Stratosphere
Choose the correct answer from the options given below: Choose the correct statement from the following:
(A). Water has highest density at 4°C
(B). Freezing point of water is 0°C
(C) An Ice cube does not completely dip in water, rather floats on water in a glass.
(D). Addition of common salt reduces freezing point of water.
Choose the correct answer from the options given below:
