Question

What is the electron configuration of $Au+$ ?

Answer 1

Hint : Electronic configuration can be written only if we know the atomic number of the elements because the atomic number gives us the number of electrons of the atoms. Gold has atomic number $79$ .

Complete Step By Step Answer:
If we know the periodic table then from there we can find that the atomic number of gold is $79$ . Atomic number tells us about the number of electrons and protons in an atom.
Electronic configuration represents the number of electrons assigned to each orbital, subshell and shell of an atom. There are many rules that govern the electron filling in the atom. All the rules and the number of total electrons help in writing the Electronic configuration of an atom. After studying about the orbitals, rules were made so as to fill the electrons in those orbitals. Aufbau’s stated a law after certain experiments. There were three rules for electronic configuration.
$(n+I)$ rule – It tells us in which subshell the electron goes first . Electrons enter in that subshell first which has the least value of . $(n+I)$ This is because that subshell has the lowest energy level.
Hund’s rule of maximum multiplicity – Electrons is placed so as to obtain maximum multiplicity which is obtained by putting electrons of the same spin in different orbitals.
Pauli’s exclusion principle – It stated that no two electrons can exist with all four same quantum numbers. -Following all these rules, we can write the electronic configuration.
The electronic configuration of gold is given as; $1{{s}^{2}}2{{s}^{2}}2{{p}^{6}}3{{s}^{2}}3{{p}^{6}}3{{d}^{10}}4{{s}^{2}}4{{p}^{6}}4{{d}^{10}}5{{s}^{2}}5{{p}^{6}}4{{f}^{14}}5{{d}^{10}}6{{s}^{1}}$

Additional Information:
$S$ subshell has one orbital and p subshell has three orbital. The order of electron orbital energy levels, starting from least to greatest, is as follows: $1s,\text{ }2s,\text{ }2p,\text{ }3s,\text{ }3p,\text{ }4s,3d,\text{ }4p,\text{ }5s,\text{ }4d,5p,6s,4f,5d,\text{ }6p,\text{ }7s,\text{ }5f,\text{ }6d,\text{ }7p.$

Note :
Remember that many elements do not follow this law and so their configuration is different from that depicted by the law. Lanthanoid and actinoid series do not follow this law. Also elements like $Nb,\text{ }Cu,\text{ }Cr,\text{ }Mo,\text{ }Tc,\text{ }Ru,\text{ }Rh,\text{ }Pd,\text{ }Ag,\text{ }Au,\text{ }Pt$ do not follow this law.