Which element is not balanced in this equation?
mg0+2 > mgcl2+li20

a. cl
b. all elements are balanced
c. mg
d. li

- Group 7th A (17) and receives 1 electron.

Explanations:- Looking at the given electron configuration the element has 7 electrons in the outer most shell(valence shell) and so it belongs to the 7th A group(17) of periodic table. This group elements are known as halogens.

To complete the octet means completing 8 electrons to their outer most shell,  this group elements receive one electron from another element during bond formation.

The given electron configuration is of Fluorine and it's atomic number is 9. Out of these 9 electrons, 2 electrons are present in inner shell and 7 electrons are present in outer most shell which is also the group number.

Noble gases are considered as the most stable elements and so all the other elements try to get their nearest noble gas electron configuration. Nearest noble gas to F is Ne and it has total 10 electrons. So, F receives one electron to look like Ne.