The two bonding mechanisms for the elements of the Periodic Table are defined. These are for the standard bond stretching effect and for a newly recognized and developed bond bending-bond shearing effect. This work involves the interpretation, definition and utilization for the bond bending-bond shearing function at the atomic bonding scale. Section 2 provides the relevant information. The solids forming elements of the Periodic Table are used to form the complete spectrum of the related properties needed for the ductile versus brittle assessments. The Poisson's ratios for these pure materials forms have the prime role in the methodology that is developed. A particular value of the ratio of the bond bending-bond shearing property to the bond stretching property is shown to divide the elements into their separate ductile and brittle groupings for the state of uniaxial tension. It is found that the numbers of elements in each group, ductile vs. brittle, are in approximate balance. The most ductile elements are gold, lead and thallium while the most extreme brittle element is beryllium.

定义了元素周期表元素的两种键合机制。这些用于标准的粘合拉伸效应和新发现和开发的粘合弯曲-粘合剪切效应。这项工作涉及原子键合尺度上键弯曲-键剪切函数的解释、定义和利用。第 2 节提供了相关信息。元素周期表的固体形成元素用于形成韧性与脆性评估所需的相关特性的完整谱。这些纯材料形式的泊松比在所开发的方法中起主要作用。显示了键弯曲-键剪切性能与键拉伸性能之比的特定值，以将元素分为其单独的延性和脆性组，用于单轴拉伸状态。发现每组中的元素数量，韧性与脆性，大致平衡。最具延展性的元素是金、铅和铊，而最易碎的元素是铍。