Give the symbols for 4 species that are isoelectronic with the calcium ion, Ca2+

Solubility would be your answer.

Starsstars are giant balls of hot gases that can produce their own light. stars give out energy by converting hydrogen gas into helium in their cores. stars are gigantic in size and have immense gravitational attraction. the sun is a medium sized star that gives us energy and makes life on earth possible.planetsplanets are large (almost) spherical objects that revolve around the sun. planets move in fixed orbits around the sun. there are 8 planets in our solar system. planets may be made of rocks, metals, gases like hydrogen, nitrogen and methane. the earth is also a planet and is the only place in the universe that we know that supports life. planets that revolve around other stars are called exoplanets.satellitessatellites are objects that revolve around planets. they form the essential part of the celestial bodies. these may be of natural origin or sent by humans. the moon is a natural satellite of the earth and revolves around it because it is bound by the earth’s gravitational pull. man also has placed artificial or man-made satellites around the earth and other planets to study them and for communication purposes.i think this is correct not 100%

Electricity is conducted when charges move from one place to another. in metals, the conductivity is due to delocalized electrons that can wander all over the place. you're probably already familiar with this.in solid ionic compounds, on the other hand, the ions aren't going anywhere. the cations and anions all attract themselves into a nice lattice and they're stuck there until they have a better reason to wander off. no moving ions = no electricity.however, if you melt an ionic compound or dissolve it in water, these ions are now free to move around. as a result, the solution can be made to conduct electricity.think about this, in solid form the outer shells of the elements are filling each other thus neutralizing the substance, but when you separate the ions (atoms of each element) their shells have space that needs to be filled or emptied, so they want to gain or loose electrons to have a full energy level. because they want this the electrons are able to move and "bounce" from ion to ion.i believe this is correct not 100%