Which of the following elements does not form a monatomic ion?

Helium

Explanation:

Hi, Helium is the only one in that list that belongs to the noble gases (group 18 of the periodic table).

This gases have the characteristic of being stable in a monoatomic molecule

Why? Becuase they have their last atomic level with a completed octet of electrons and cause of that, they don't have the need to gain, lose or share electrons with other atoms.

answer

fusion: the energy source of stars. the energy released from the collapse of the gas into a protostar causes the center of the protostar to become extremely hot. when the core is hot enough, nuclear fusion commences. fusion is the process where two hydrogen atoms combine to form a helium atom, releasing energy.

hope it

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !