Answer:Valence Shell
Explanation: The Valence Shell is the outermost orbital of an atom. The Valence Shell electrons are used in making chemical bonds and are the reason the atom has its physical and chemical properties.
Salt and water is a homogeneous mixture. Sand and water,salad dressing,soil are heterogeneous mixtures.
When we have Avogadro's number with four significant figures 6.022 x 10^23
and we have also this number 2.055 is also with four significant figures so,
the number of atoms = Avogadro's number / 2.055
= 6.022 x 10^23 / 2.055
= 2.930 x 10^23
and we can see that the result is number with four significant figures
Weak acids ionise partially and their ionisation is reversible and the ions may react to give back the acid molecule (sorry i'm not sure if i am answering your question though)