Advertisements
Advertisements
प्रश्न
An ionic compound crystallises in FCC type structure with ‘A’ ions at the centre of each face and ‘B’ ions occupying corners of the cube. The formula of compound is _______.
विकल्प
AB4
A3B
AB
AB3
Advertisements
उत्तर
'A' ions are at the centre of each face. There are six face centres and each contributes one half to the unit cell. Total number of A ions present per unit cell
`=6 xx 1/2 = 3`.
'B' ions occupy corners of the cube. There are 8 corners and each contributes one eight to the unit cell.
Total number of B ions present per unit cell
`=8xx1/8=1`.
The formula of a compound is A3B
Hence, the correct answer is A3B.
APPEARS IN
संबंधित प्रश्न
The major binding force in diamond is_______________ .
(a) Covalent bond
(b) Ionic bond
(c) Metallic bond
(d) Co-ordinate covalent bond
What is the covalency of nitrogen in N2O5?
Give an example each of a molecular solid and an ionic solid.
Ionic solids conduct electricity in molten state but not in solid state. Explain
What type of solids are electrical conductors, malleable and ductile?
Explain the basis of similarities between metallic and ionic crystals.
Explain ionic solids are hard and brittle.
Define Anisotropy.
A compound is made up of two elements X and Y and crystallizes in bcc structure. Atoms of X are present at the corners of the cube. Atoms of Y are present at the centre of the cube. The formula of the compound is ______.
Sodium crystallizes in bcc structure. If the edge length of unit cell is 4.3 × 10-8 cm, the radius of Na atom is ______.
An ionic compound AxBy crystallizes in fcc type crystal structure with B ions at the centre of each face and A ion occupying corners of the cube. the correct formula of AxBy is
Solid CO2 is an example of ____________.
Assertion: monoclinic sulphur is an example of a monoclinic crystal system
Reason: for a monoclinic system, a ≠ b ≠ c and α = γ = 90°, β ≠ 90°
Classify the following solid.
P4
Classify the following solid.
Brass
Classify the following solid.
Iodine
Select the INCORRECT match:
Which of the following is TRUE about molecular solids?
____________ is an example of molecular crystal.
Dry ice is an example of ____________.
Fullerene is an example of ____________.
Which among the following is NOT a polar molecular solid?
Lithium crystallizes into body centered cubic structure. What is the radius of lithium if edge length of it's unit cell is 351 pm?
Which among the following is an example of network solid?
Brass is an example of ____________.
Solid X is a very hard electrical insulator in solid as well as in molten state. It melts at extremely high temperature. Solid X is a ____________.
What type of interaction hold the molecules together in a polar molecular solid?
Which among the following is an example of non-polar molecule?
MgO has the structure of NaCl. The coordination number of the ions in MgO is ____________.
An AB2 type structure is found in ____________.
Solid CH4 is ____________.
An example of a covalent crystalline solid is ____________.
Which of the following exists as covalent crystals in the solid state?
The major binding force of diamond, silicon and quartz is ____________.
Which of the following is a network solid?
Iodine molecules are held in the crystals lattice by ______.
Which of the following cannot be regarded as molecular solid?
(i) SiC (Silicon carbide)
(ii) AlN
(iii) Diamond
(iv) I2
Which of the following is not true about the ionic solids?
An excess of potassium ions makes KCl crystals appear violet or lilac in colour since:
(i) some of the anionic sites are occupied by an unpaired electron.
(ii) some of the anionic sites are occupied by a pair of electrons.
(iii) there are vacancies at some anionic sites.
(iv) F-centres are created which impart colour to the crystals.
Why are liquids and gases categorised as fluids?
Inspite of long range order in the arrangement of particles why are the crystals usually not perfect?
A crystal with a ≠ b ≠ c and α = β = γ = 90° is
Who introduced the term covalent bond?
Calculate the angle at which first order reflection will occurs in an X-ray spectrometer when x ~ rays of wavelength \[\ce{1.54 \overset{\circ}{A}}\] are diffracted by the atoms of a crystal given that inter planer distance is \[\ce{0.04 \overset{\circ}{A}}\]
A reddish-pink substance on heating gives off a vapour which condenses on the sides of the test tube and the substance turns blue. If on cooling water is added to the residue it turns to original colour. The substance is ______.
Among the following which is the best description of water in the solid phase?
Mention the res of the following solid:
CO2
Quartz is which type of crystal?
