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4 years ago

PLEASE. Arrange from highest to lowest highest melting point; NaCl, MgO, KBr, RbI. Explain your rationale.

Chemistry

1 answer:

Dmitry [639]4 years ago

8 0

Answer:

MgO> NaCl > KBr >RbI

Explanation:

Lattice energy refers to a measure of the energy contained in the crystal lattice of a compound. It is equal to the energy that would be released if the component ions were brought together from infinity. It is also defined as a measure of the energy released when ions are combined to make a compound or a measure of the cohesive forces that bind ions together in an ionic solid.

Melting points of ionic substances depend on their relative lattice energies. Similarly, the lattice energy depends on the size of the ions in the ionic solid. The smaller the sizes of the component ions, the greater the lattice energy. It can be seen that the sizes of cations and anions decrease steadily from RbI to MgO hence the lattice energy and melting point of the ionic solids increases in the order shown in the answer. The smaller the component ions in the lattice the greater the melting point of that ionic solid.

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alex41 [277]

Answer: Step 2 in the given mechanism is the rate determining step

Explanation:

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The intermediate reaction of the mechanism follows:

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4 years ago

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Explanation:

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3 years ago

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Vera_Pavlovna [14]

Answer:

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Explanation:

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4vir4ik [10]

Answer:

See the example below.

Explanation:

Let us make an example with a group of compounds to apply the general trends of electronegativities within families to find which compound has a greater difference in electronegativities.

Use this group.

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b. HI

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Br, I, F, and Cl belong to the halogen family (group or column 17 of the periodic table).

Electronegativity is a relative measure of how strong an atom atracts the bonding electrons in a compound.

Since the strength of attracion of the valence electrons by the nucleus of an atom decreases as the size of the atom incease, in a family of elements (same group) the electronegativity decreases as you go down in the group.

The order of the halogens from top to bottom in the column in the periodic table is F, Cl, Br, and I.

Thus, the order of their electronegativiies is: F > Cl > Br > I. F is the most electronegative atom, and all those elements have higher electronegativy than H. (The electronegativiy of I is 2.66 and the electronegativity of H is 2.2). Thus, including H, the rank of the electronegativities is F > Cl > Br > I > H.

Thus, the greater difference in electronegativities is for HF (option a.).

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