Which one of the following properties changes with valency

Equivalent weight is the only property among the options that directly changes with valency. It is defined as the ratio of the atomic weight (or molecular weight) of a substance to its valency or n-factor [t1][t2]. The mathematical relationship is expressed as: Equivalent Weight = Atomic Weight / Valency [t3][t4]. For instance, the equivalent weight of oxygen is 8.0 grams because its atomic weight (16.0) is divided by its usual valency of 2 [t4][t8]. In contrast, atomic weight and molecular weight are intrinsic properties of atoms and molecules based on their isotopic composition and mass, which do not fluctuate based on the number of bonds formed [t9]. Density is a physical property representing mass per unit volume and is not a function of valency. Therefore, if an element exhibits variable valency, its equivalent weight will change accordingly for different reactions [t3][t6].

Sources

1. [1] https://www.sciencedirect.com/topics/engineering/equivalent-weight
2. [2] https://en.wikipedia.org/wiki/Equivalent_weight