Consider the following statements about crystalline solids:
(in) molecules or atoms in molecular solids are held together by intermolecular forces.
(ii) metallic solids have atoms in the points of the crystal lattice.
(iii) ionic solids have formula units in the point of the crystal lattice.
(iv) atoms in covalent-network solids are connected via a network of covalent bonds.
which of the statements is false?

Statements (iii) is false

Explanation:

Ionic solids do not have formula units in the points of the crystal lattice, instead, they have ions in the points of the lattice.

Consider the example of NaCl. Here Na⁺ is the cation while Cl⁻ is the anion, together they form a cubic unit cell by the electrostatic attraction between them. A crystal lattice defines the arrangement of atoms or molecules in a crystal, and the points on it represent the species which are responsible for the ordered arrangement. In the case of ionic solids, these species are ions, as they are responsible for electrostatic attraction or repulsion causing an ordered arrangement around it.

explanation:

venn diagram is pictorial representation with of circles showing the relation between two finite sets or things. the intersection part of two circles conveys the relation present in between those sets or things.

here in the venn diagram of sand and salt two circles represent sand and salt. but the area falling under the intersection of these circle represents the mixture of sand and salt.

so, in a venn diagram the mixture will be placed in a middle that is in between the intersection of two circles.