What are the periodic trends of ionic radii? check all that apply. a. ionic radii tend to increase down a group. b. ionic radii tend to decrease across a period. c. anionic radii tend to increase across a period. d. cationic radii tend to decrease across a period. e. ionic radii increase when switching from cations to anions in a period.

Ionic radii tend to increase down a group, so A, cationic radii tend to decrease across a period, so D, Ionic radii increase when switching from cations to anions in a period, E.

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.