It's B, because a negative charged Ion is an anion. And since it's 1- ,one valence electron is been added to H. So it has 2 valence electrons.
5= Elemental hydrogen, nitrogen, oxygen, fluorine and chlorine are all gases at room temperature,
Answer: 12 neutrons
Explanation: The mass number of an element tells us the number of protons AND neutrons in an atom (the two particles that have a measurable mass). Sodium has a mass number of 23amu. Since sodium has 11 protons, the number of neutrons must be 23 – 11 = 12 neutrons.