Which equation correctly represents the first electron affinity (ea1) of calcium?

Answer : The correct equation will be:

Explanation :

Electron affinity : It is defined as the addition of electron to the atom or to the ion. The atom or ion is always in gaseous phase.

In other words we can say that, the gaining of electrons is said to be an electron affinity.

As, the given element is a calcium metal, so it will gain an electron to form a anionic atom.

The balanced and correct equation for first electron affinity of the calcium will be:

the answer to your question is c.

if you read the house of usher you should know that the house was haunted