Answer:
Monatomic molecule
Explanation:
Each helium atom has 2 electrons, which is already the maximum no. of electrons that can fit in the first electron shell. When the outermost electron shell is full (2 for the first layer, 8 for others), the atom is stable.
Helium atom itself is already stable, so it doesn't need to combine with another helium atom to form a molecule, hence we call it monatomic.
If u disturbed equilibrium position then this principal comes into effect deciding how to counteract the disturbance.
They will attract each other when brought close but when they touch the glass rod will become a negative charge and will repel each other