I think the correct answers from the choices listed above are the first, third and the last option. Ionic compounds are compounds that dissociates into ions when in aqueous solution. From the list, NH4Cl, KF and MgO are the ionic compounds. Hope this answers the question.
4 protons the number of proton has the same number of electron [which is the same as atomic number]
Gravity is the force that keeps the planets in orbit.
Answer:
Helium
Explanation: The ionization energy decreases from the top to bottom in groups. And increases from left to the right across a period. Therefor Helium has tge largest first ionization energy, while francium has one of the lowest.
