Consider the following general characteristics of alkali metal down the groups:I. The atomic and ionic radii increase from Li to Cs with the increasing atomic number due to the addition of new shells. II. Hardness of alkali metals decreases from Li to Cs with decreasing interatomic interactions.III. Melting and boiling points generally decrease from Li to Cs with the decreasing interatomic interactions.IV. Electropositive character increases from Li to Cs with decreasing I.E values.Which of the above statement is correct?

Explanation

All of the statements are correct. The atomic and ionic radii increase from Li to Cs with the increasing atomic number due to the addition of new shells. This is because as the atomic number increases, the electrons are added to shells that are further away from the nucleus. This makes the electrons more loosely held and the atom or ion larger. Hardness of alkali metals decreases from Li to Cs with decreasing interatomic interactions. This is because as the atoms get larger, the interatomic interactions become weaker. This makes the atoms less able to resist deformation and the metal less hard. Melting and boiling points generally decrease from Li to Cs with the decreasing interatomic interactions. This is because the melting and boiling points are a measure of the strength of the interatomic interactions. As the interatomic interactions decrease, the melting and boiling points also decrease. Electropositive character increases from Li to Cs with decreasing I.E values. This is because the electropositive character is a measure of how easily an atom loses electrons. As the ionization energy decreases, the atom becomes easier to ionize and the electropositive character increases.