The electrons in actinium are disposed on seven energy levels.
Actinium has seven electron shells.
The electrons in actinium are disposed on seven energy levels.
Actinium has seven electron shells.
Actinium has seven electron shells.
The electrons in actinium are disposed on seven energy levels.
Bromine has 4 energy shells.
Silicon has 3 energy shells.
A sodium atom has 3 energy shells.
Berkelium has seven electron shells.
2
All the isotopes of actinium has 89 protons.
One atom; actinium is an element, not a molecule.