pe.ri.o.dic.i.ty
n.（名词）【复数】 pe.ri.o.dic.i.ties The quality or state of being periodic; recurrence at regular intervals.周期性：周期出现的性质或状态；以固定的间隔而发生The tendency of chemical elements with similar positions in the periodic table to have similar properties.周期律：化学元素在周期表中有相似位置时具有相似特性的趋势The position of an element in the periodic table.元素在周期表中的位置
