Ionic compound are those compounds which are made up of ions. The ion which has tendency to loose electrons is said to cation (positive charge) such as metals whereas ion which has tendency to gain electrons is said to anion (negative charge) such as non-metals.
Calcium nitrate is quite soluble in water due to very low lattice enthalpy in comparison to other ionic compound. With lower lattice enthalpy, less energy is required for the dissociation of calcium nitrate and it get dissolves in water than other three compounds. Moreover, hydration energy is higher for calcium nitrate which make its solubility higher in water than other ionic species.
Thus, 
is correct answer.
Answer:
The particle model does not take into account: the size and shape of particles. the space between particles.
To answer this problem, we need to count the electrons in the given configuration. The complete configuration is 1s2 2s2 2p6 3s2 3p6. There are 2+2+6+2+6 equal to 18 electrons. We find next the element with an atomic number of 18. That element is noble gas argon.
Answer: A)There is a high ratio of energy to cost
Positives:
A Chunk of Uranium can power a city a lot longer than a chunk of coal.
It also does not contribute to pollution since what comes out of the tower is steam.
Negatives:
It is very expensive to build and maintain a nuclear power plant at first so investors whom want money up front are more reluctant to loan money for one.
If the plant does melt down it is very bad for the enviroment and its people, for example Chernobyl Nuclear Power Plant in the Ukraine will not be able to be lived in for approximently 20,000 years.
The answer is, All of the above
