The electron affinity of an element is positive if energy is absorbed during the process of accepting an electron and negative if energy is released during the process. Using the electron configuration of the atom or ion undergoing the addition of an electron, predict whether the electron affinity will be positive or negative for the following reactions, and classify them accordingly. Atom or ion Electron configuration
Ne 1s22s22p6
Br 1s22s22p63s23p64s23d104p5
Na 1s22s22p63s1
Mg 1s22s22p63s2
Cl 1s22s22p63s23p6

See explanation

Explanation:

Ne is a noble gas. It already has an octet of electrons hence, the electron affinity of neon is negative.

Br is a halogen, halogens need one electron to complete their octet. The electron affinity for bromine is negative.

Sodium is a metal that has only one electron in its outermost shell. The electron affinity of sodium is positive.

Magnesium is a metal having two electrons in its outermost shell. The electron affinity of magnesium is positive.

Chlorine is another halogen, energy is released when an electron is added to chlorine hence the electron affinity of chlorine is negative.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.