The mass number of Fe2+ is 56. How many neutrons are there in a single Fe2+ atom?

There are 30 neutrons in a single Fe2+ atom.

30

Explanation:

(i dont know if its correct i am in a rush,)

Number of neutrons = 56 – 26 = 30. Thus there are 30 neutrons in a single $F{{e}^{2+}}$ atom. Note: Neutron is generally a subatomic particle which is neutral in charge. Mass of the neutron is slightly greater than the mass of the proton.

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.