Question

4. Which attribute is larger for each of the following pairs, based on the periodic trends discussed in class? Justify your reasoning. Some pairs may be too close to tell based on trends alone; if this is the case, state this along with your justification. Do not use literature values to justify your answer!

A) Se2- and As3-; ionic radius

B)Cr and Zr; atomic radius

C) Ca2+ and Mg2+; ionic radius

D) O and N; electron affinity

E) Cu+ and Cu2+; ionization energy

F) Mn and Ag; ionization energy

G) Mo and Co; electronegativity

Answer 1

A) As^3- will have the greater ionic radius as it is having greater negative charge. The higher negative charges will have a lesser attraction from the nucleus.

B) Zr will have a greater radius than Cr because the valence electrons in Zr is in 5th orbit where as the valence electrons in Cr are in 4th orbit.

C) Ca²⁺ will have the higher radius because it is present in higher orbit than Mg²⁺

D) N will have the higher radius because in periods from left to right the atomic size decreases.

E) If the positive charge on the ion increases it decreases the size of the ion. HEnce Ca²⁺ is having lesser size.

F) Ag will have the higher radius than the Mn because of the number of shells increases in the Ag.

G) Mo will have the higher radius than the Co because of the number of shells are more in Mo.