Answer:
2 8 8 2 is a correct answer
Answer is 56 protons and 56 electrons.
<em>Explanation;</em>
Atomic number is equal to number of protons. Hence, when the atomic number is 56, it means that atom has 56 protons.
When the element is in neutral state, number of protons = number of electrons. Hence, we can say that barium atom has 56 electrons.
But same element can have different number of neutrons. Those are called isotopes. Hence, we cannot say that there are 56 neutrons in barium atom without having its mass number. (Mass number = number of protons + number of neutrons)
Just 2 valence electrons.
Hydrogen already has one to start with, as well. With the exception of hydrogen and helium, all other atoms need 8 valence e-
