Question

Predict block period and group to which iridium belongs (atomic number 77) and justify your answer

Answer 1

Answer: Block-d, period-6, and Group-9

Explanation: Iridium is a element with atomic number of 77, and this it contains 77 electrons. The nearest noble gas is Xenon with atomic number of 54.

Thus the electronic configuration is:

$Ir:[Xe]4f^145d^76s^2$

As the last electron enters d orbital, it is a d block element. The valence electron is in 6th shell, thus the period is 6.

For a d block element, Group no. = no. of electrons in (n-1) d subshell + no. of electron/s in ns shell.

Group no. = 7+2 = 9.