Recall that the maximum number of electrons in the $$n=1$$ orbit is $$2$$. So, if an atom has only the $$n = 1$$ orbit, $$2$$ electrons in the $$n=1$$ orbit are sufficient to make the atom stable.
• $$\text{Hydrogen} = 1$$, $$\text{Helium} = 2$$
• $$\text{Hydrogen} = 1$$, $$\text{Helium} = 0$$
• $$\text{Hydrogen} = 7$$, $$\text{Helium} = 6$$
• $$\text{Hydrogen} = 1$$, $$\text{Helium} = 6$$