Which of the following factors contributes to increase in atomic size within a group in the periodic table as the atomic number increases

Both models are effective because they show the valence electrons, and these valence electrons indicate the reactivity of an element.

Answerd. may include all of these are many definitions of bases: the  brønsted-lowry definition of acids and bases says that bases are proton acceptors.the arrhenius definition of acids and bases says that bases increase [oh⁻] in solution (thereby producing oh⁻ ions)the lewis definition of acids and bases says that bases donate electron pairs.therefore, the sensible answer is that a base may include all of the described characteristics.