Periodic Proper...

The following question has four choices out of which ONLY ONE is correct.

Which of the following orders of elements is correct in terms of decreasing ionisation enthalpies?

If the valence shell electronic structure of an element is ns²np⁵, then to which group of the periodic table does the element belong?

The elements with atomic numbers 4, 12, 20, 38 and 56 belong to the group of

To which group of the periodic table does the element with electronic configuration 1s², 2s², 2p⁶, 3s², 3p⁶, 3d¹⁰, 4s², 4p⁶, 4d¹⁰, 5s², 5p³ belong?

Iron triad of elements also contains

If we have an element with atomic number 115, then which of the following statements is correct about this element?

Which of the following elements is a metalloid?

The screening effect of s-orbital electron is

The electronic configurations of four elements are given as follows:

(1) [Xe] 6s¹
(2) [Xe] 4f¹⁴, 5d¹, 6s²
(3) [Ar] 4s², 4p⁵
(4) [Ar] 3d⁷, 4s²

Which of the following statements about these elements is incorrect?