Arrange the following:

(a). Element of group 1, in increasing order of their reactivity.

(b). Element of group 17, in decreasing order of their reactivity.

(c). He, Na, Mg (increasing order of their melting point)

(d). Chlorine, Sodium, and Magnesium (in increasing order of their reducing character)

(a). The following elements are present in group 1 are:

• Lithium(Li), Sodium(Na), Potassium(K), Rubidium(Rb), Cesium(Cs), Francium(Fr)

Reactivity:

• As we move downward the capacity of losing electrons will increase because metallic characters increase so, the reactivity of these elements will also increase.
• So, the increasing order of reactivity of the group1 is as follows:
• Li<Na<K<Rb<Cs<Fr

(b). The following elements are present in group 17 are:

• Florin(F), Chlorine(Cl), Bromine(Br), Iodine(I), Astatine(At)

Reactivity:

• As we move downward in group 17 the size of elements increases so, the capacity to gain electrons will decrease hence the reactivity of group 17 decreases as we move downward.
• So, the decreasing order of reactivity of the group17 is as follows:
• F>Cl>Br>I>At

(c). The periodicity of melting and boiling point is not regular in a periodic table.

• It first increases and then decreases and then again started to increase in non-metals.
• So, the increasing order of melting points for these elements will be:
• He<Na<Mg
• metals and nonmetals form ionic bonds which are the strongest bond and hence need more energy for breaking while helium is a noble gas that doesn't react with any other elements hence is melting and boiling points are low.

(d). Reducing character:

• It is totally based on the capacity of losing electrons. The more the capacity to lose electrons the more the power of reduction.
• So, the increasing order of reducing character will be:
• Cl<Mg<Na
• Chlorine is a non-metal and hence it has a capacity of gaining electrons and are good oxidizing agents while sodium and magnesium are the metals that have the capacity of losing electrons and hence they are good reducing agents.