How many na+ ions are at least partially within the unit cell?

A unit cell is a simplest repeating unit in a crystal in which particle are freely vibrating

Sodium chloride having face centered cubic lattice in which sodium and chloride ion are arranged and vibrating.

The sodium ion are arranged on eight corners of the cube whereas they are also present on all the six centres of all six faces.

Thus, number of Na+ ion  

Hence total of 14 sodium ions are present in NaCl lattice.

true

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answer: option (b) is the correct answer.

explanation:

a covalent bond is formed by sharing of electrons. whereas polarity arises due to difference in electronegativity of two atoms.

therefore, more is the electronegativity of an atom which combines with the titanium, more readily it will induce a partial positive and negative charge.

thus, out of the given options fluorine is most electronegative and has an incomplete octet. therefore, it will readily combine with titanium to share the electrons and complete its octet.