Which of the following is not Dobereiner triad?

What is the oxidation state of Mn in KMnO4?

The elements, Unnilhexium and Seaborgium are the same.

______ has both the characteristics of Alkali metals and halogens.

What’s the atomic number of the element Copernicium?

The p-block elements along with s-block elements are called as ____ elements.

The horizontal rows in Mendeleev’s periodic table were called as ______

Ionization energies are always positive.