What energy is required to move from ca+ca+ to ca2+ca2+ + e−e−?

Second Ionization energy

Explanation:

Let us write the reaction equation properly:

                  Ca⁺ → Ca²⁺ + e⁻

In the reaction above, we see that calcium goes from a single charge to being doubly charged by losing an electron.

Different atoms binds their valence electrons with different amount of energy. We must supply enough energy to remove the most losely held electrons in an atom. This amount of energy required is called the ionization energy.

The first ionization energy removes the outermost electron and makes the atom to become an ion.

in 1783 cavendish was working with his hydrogen gas and found that when he burned it and condensed the vapor it was water. this was very significant since it disproved the greek theory of elements completely since water was not a simple substance but the product of two gases. it was lavoisier who hearing of the experiment gave cavendish's gas the name hydrogen ("water-producer") and added that hydrogen burned by combining with oxygen and that water was a hydrogen-oxygen combination.

explanation:

no, the red giant is the hottest with 2.00.000.000 degrees celsius. while the white dwarf only 25,000 degrees celsius.