Which of the following groups contains members with similar chemical reactivity? a) sc, y,zr b) li, be, c c) c, n,o d)be, mg, sr

Answer is: D) Be, Mg, Sr.

Beryllium, magnesium and strontium are alkaline earth metals (group 2 of Periodic table of elements).

The elements have very similar properties.

Alkaline earth metals have in common an outer s- electron shell (two electrons). For example, magnesium atom.

Atomic number of magnesium (Mg) is 12, it means that it has 12 protons and 12 electrons.  

Electron configuration of magnesium atom: ₁₂Mg 1s² 2s² 2p⁶ 3s².

"record the time to complete a chemical reaction" would most likely be part of a lab procedure.

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.