how many protons , neutrons and electrons ar present in an atom of hafnium , hf , with a mass number of 178?

This image is an example of a(n) a) atom. b) compound. c) mixture. d) molecule.

Sugar is dissolved in water. which is the solute? sugar neither both water

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules