Tag: chemistry

Common salt (NaCl) is an ionic compound consisting of a lattice of Na+ and Cl- ions.

Melting point of an ionic compound is determined by the electrostatic attraction between cations and anions. It takes a lot of energy to overcome this attraction to allow the ions to move freely and form a liquid. The factor witch effect melting point is charge of the ion. Since, $KCl$ has $+1$ and $-1$ charge on its' cations and anions respectively. Hence, it has the lowest melting point.

An ionic solid has some point defect but its experimental density is equal to its theoretical density. The type of defect is Frenkel effect.

When an ion leaves its correct lattice site and occupies an interstitial site, Frenkel defect is observed. Hence, the density of the crystal is not affected.

In a Schottky defect, the density of the crystal decreases.

Hence, the given statement is $\text{true}$

Lattice energy is inversely proportional to the inter-ionic distance, which is the sum of the ionic radii (Rc + Ra).

Carborundum (silicon carbide) has a giant three-dimensional network structure held by covalent bonds, making it a covalent solid.

Graphite consists of carbon atoms arranged in layers, with each atom covalently bonded to three others within the layer, making it a covalent crystal.

A covalent network crystal consists of atoms at the lattice points of the crystal, with each atom being covalently bonded to its nearest neighbour atoms.