The flame colours of metal ions are due to

Which of the following compounds exhibits metal deficiency defect?

Electron-deficient impurities are caused by the elements of which group?

Identify the defect developed when an ion of an ionic compound is missing from its regular site and occupies an interstitial position between lattice points.

Non-stoichiometric defects do not include which of the following?

An element $X$ (atomic weight = $24$) crystallises in a face-centered cubic $(FCC)$ lattice. The edge length of the unit cell is $400 \, pm$. If this lattice contains $4\%$ Schottky defects,calculate the observed density of this element in $g/cm^3$ $(N_A = 6 \times 10^{23})$.