Oxygen
undiscovered...yet, but there are a few...go forward 50 years and see
the one that is completely filled
Nobel gases are said to have completely filled third principle energy level. One example is Argon which is a noble gas.
Completely filled octet.
The external level of electrons is completely filled.
The element with a half-filled 5p level is antimony, which has the electron configuration [Kr] 4d^10 5s^2 5p^3. The half-filled 5p level stabilizes the atom, making antimony less likely to gain or lose electrons.
The element with a half-filled 5p level is antimony (Sb), which has an electron configuration of [Kr] 4d^10 5s^2 5p^3. It has five electrons in its 5p orbital, meaning it half fills the 5p level.
it is called complete or completely stable
Completely filled octet.
A noble gas is considered unreactive because it has a filled outer energy level. The full outer energy level provides stability and low reactivity, as the element does not need to gain or lose electrons to achieve a stable electron configuration.
This element is likely chlorine (Cl), which has 7 valence electrons and 3 filled energy levels with a partially filled 4th energy level.
Because platinum is a noble metal: the external level of electrons is completely filled.