Which of the following is the correct rank of increasing electron affinities (from less exothermic to more exothermic)? Select the correct answer below: Cs

The question is incomplete, the complete question is ;

Which of the following is the correct rank of increasing electron affinities (from less exothermic to more exothermic)? Select the correct answer below: O Cs <K<Na <Li O Li< Na <K <Cs O Na <Li<K <Cs OK<Cs < Li< Na

Cs< K<Na<Li

Explanation:

The electron affinity is defined as the energy released when a neutral gaseous atom accepts an electron to create a gaseous negative ion. This reaction is exothermic and leads to the evolution of heat.

When an electron is added to a metal, large energy is required since metals are usually electro positive. Electron affinity decreases down the group since electrons enter into higher energy levels further away from the nucleus. They experience lesser nuclear attraction.

This is clearly evidenced in the sharp decrease in the electron affinity of group one elements from lithium to caesium. The electron affinity of lithium is 60Kjmol-1 but decreases steadily down the group to a value of 46KJmol-1 for caesium. This explains the order chosen in the answer.

nuclear wastes can be safely disposed of

Explanation:

In comparing fossil fuel power plants with nuclear power plants, it is obvious that fossil fuel power plants lead to a large volume of emission of oxides of carbon and sulphur.

Also, a larger volume of coal needs to be burnt to generate energy compared to a minute amount of uranium fuel that can sustain a nuclear power plant for a long period of time thereby reducing the environmental damage associated with mining of the fuel.

However, the problem of nuclear waste disposal have remained a thorn in the flesh. It is often difficult to safely dispose of spent uranium fuel. This is a major disadvantage of the use of nuclear power.