In an ionic compound, the size of the ions affects the internuclear distance (the distance between the centers of adjacent ions), which affects lattice energy (a measure of the attractive force holding those ions together). Based on ion sizes, rank these compounds of their expected lattice energy..
Note: Many sources define lattice energies as negative values. Please rank by magnitude and ignore the sign. |Lattice energy| = absolute value of the lattice energy.
RbCl ,RbBr ,Rbl ,RbF

RbF>RbCl>RbBr>RbI

Explanation:

Lattice energy depends largely on the internuclear distance between two oppositely charged ions in a crystal lattice. The smaller the both ions, the greater the lattice energy of the crystal.

In the case of the compounds listed above, the cation in all the compounds is the same but the anions have varrying sizes in the order I->Br->Cl->F-. Since the smaller the ion, the greater the lattice energy, the order of decreasing lattice energies stated in the answer is thus well rationalized.

indicate valleys, hills, steepness and gentleness of slopes.

explanation:

contour lines on a map indicate elevation, or depth. numeric notations on contour lines refer to the level of elevation, or height about sea level.

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