The first is this the z effective, or how much charge is actually in the nucleus that's felt, Z or the I guess we would say the z, how much the charge is on the nucleus that holds it close together.

第一个是有效核电量，或者说实际感受到的核电荷量，又或者我想我可以说就是，使它们保持在一起的,原子核的电荷量。

麻省理工公开课 - 化学原理课程节选

In 1931, at Columbia University, Harold Yuri discovered this isotope, which has two.

931年在哥伦比亚大学，哈罗德尤里发现同位素，有两个核电荷数。

麻省理工公开课 - 固态化学导论课程节选