My answer to the question above is not the best example but I hope it will help you. <span>The Arrhenius model says that acids always contain H+ and that bases always contain OH-. </span>
<span>The Bronsted-Lowry model thinks of acids as being proton donors and proton acceptors, so bases no longer need to contain OH-, and acids donate a proton to water forming H3O+. </span>
<span>Lewis acids are electron pair acceptors, and Lewis bases are electron pair donors. For instance, H+ + OH- => H20. H+ has no electrons, so when it bonds to the Oxygen, it gains an electron pair. OH- "loses" an electron pair.</span>
The correct answer is Helium Nucleus. Hope this helps.
Elements are pure substances made up of molecules
Answer:

Explanation:
Density can be found by dividing the mass by the volume.

The mass of the water is 50.0 grams.
The volume of the water is 50.0 milliliters.

Substitute the values into the formula.

Divide.

The density of the water is 1.0 grams per milliliter. Also, remember that the density of pure water is always 1.0 g/mL or g/cm³