What is the atomic number of gold?

Ionisation energy of $Li$ (Lithium) atom in ground state is $5.4 \ eV$. Binding energy of an electron in $Li^+$ ion in ground state is $75.6 \ eV$. Energy required to remove all three electrons of Lithium $(Li)$ atom is ........... $eV$.

Which of the following atoms has the lowest ionization potential?

If elements with principal quantum number $n > 4$ were not allowed in nature,then the number of possible elements would be

In a $He-Ne$ laser,the metastable state exists in:

The spin quantum numbers $+1/2$ and $-1/2$ indicate that...