所有的钒盐都是有毒的，但少量钒盐又是饲料的一种添加剂。（)

三采表活剂可以分为()类、磺酸盐类、羧酸盐类等。

钛是一种具有生物活性的金属。(  )

同一族过渡元素从上到下氧化态的变化规律是趋向形成稳定的高氧化态。(  )

如果某金属元素单质不能与盐酸作用，则该金属与其离子所组成电对的标准电极电势一定大于零。(  )

水溶液中，铬、钼、钨都是高氧化态的化合物稳定，都可以形成同多酸或杂多酸，其他副族元素无此共性。(  )

Which typical oxides and hydroxides can be formed by Lanthanide elements？

The order of elution of the transuranium elements from an ion exchange resin parallel that of the lanthanoid elements. Suggest an explanation for this observation.

Suggest a reason why, of the Ln3 + ions, the magnetic moment of only Gd³⁺is in agreement with the moment calculated from the spin-only formula.

Which tripositive lanthanoid ion(s)is(are)most likely to react with chromium(II )chloride？ What products are expected？ Explain.