Question

Explain the following trends in lattice energy. (Select all

thatapply.)
(a) MgO > MgCl2

Theoxide ion is more electronegative than the chlorideion.
Theoxide ion has a -1 charge; whereas the chloride ion
is-2.
Theoxide ion is bigger than the chloride ion.
Theoxide ion has a -2 charge; whereas the chloride ion
is-1.
Theoxide ion is smaller than the chloride ion.

(b)NaCl > RbBr > CsBr
NaCl is smaller than RbBr andCsBr.
TheCs cation is larger than the Rb cation.
Theions in CsBr and NaCl are +2 and -2; whereas in RbBr they
are +1and -1.
CsBr is smaller than RbBr andNaCl.
TheNa cation is larger than the Cs cation.
Theions in CsBr and RbBr are +2 and -2; whereas in NaCl they
are +1and -1.

(c) BaO> KF
Theions in KF are +2 and -2; whereas in BaO they are +1
and-1.
Theions in BaO are +2 and -2; whereas in KF they are +1
and-1.
KFis smaller than BaO.
Fluorine is more electronegative thanoxygen.
BaOis smaller than KF.

Answer 1

A) Theoxide ion is bigger than the chloride ion.

B) NaCl is smaller than RbBr andCsBr.

C) Theions in BaO are +2 and -2; whereas in KF they are +1

and-1.

Explanation: The lattice energy depends on the relative sizes of the ions. In A, oxide ion is bigger than the chloride ion since ionic sizes of anions increases with magnitude of charge. In B, the ionic sizes of cations increases down the group hence the stated order. In C, the magnitude of charge becomes a deciding factor. The larger the magnitude of charge, the higher the lattice energy.

Answer 2

Here are key points on lattice energy

Lattice energy (L.E) is the energy required to separate a mole of an ionic solid into gaseous ions.

• L. E cannot be measured empirically, but it can be estimated using the Born-Haber cycle or calculated using electrostatics.

• The charge and radius of the bonded ions are two main factors that contribute to the magnitude of the L.E.

Step-by-step explanation:

About the trend Yes/No are included to the details.

a)

1. True - (as charge increases, lattice energy increases)

2. False - (Oxide and chloride both have -1 charge)

3. False (The chloride ion is bigger having a bigger radius)

4. False - (the charges quoted are incorrect )

5. True

(b)

1. True - (it has the smallest radius)

2. True

3. False (the ion in all are +1 and -1)

4. False

5. False

6. False

(c)

1. False - ( BaO +2 and -2 while KF +1 and -1)

1. False - ( BaO +2 and -2 while KF +1 and -1)

2. True

3. False

4. True

5. True