Question

give the electron configuration for osmium (os)
you must use the noble gas configuration (the shortcut)

Explanation:

Step1: Identify noble - gas core

Osmium (Os) has an atomic number of 76. The noble gas before it is xenon (Xe) with an atomic number of 54. So we start with [Xe].

Step2: Fill remaining electrons

After [Xe], we start filling the 6s orbital. The 6s orbital can hold 2 electrons, so we have 6s². Then we move to the 4f orbitals (which can hold 14 electrons) and 5d orbitals (which can hold 10 electrons). After filling 6s², we need to place 76 - 54 - 2=20 more electrons. The 4f sub - shell is filled before the 5d sub - shell. The 4f sub - shell is filled with 14 electrons and then we fill the 5d sub - shell with 6 electrons. So the electron configuration is [Xe]6s²4f¹⁴5d⁶.

Answer:

[Xe]6s²4f¹⁴5d⁶