What is the ground state configuration of a magnesium atom?

2-8-2

Explanation: look at the regents chemistry reference table (easiest way). If you understand what subshells are then you should know (or not) that S subshells only contain 2 electrons and the first shell only has one orbital (increases as the shells do). The second shell contains S and P (# of ē maxed at 6) subshells and the third shell has S, P, D (# of ē maxed at 10). The electron configuration for ground state would then be: 1s² 2s² 2p^6 3s²

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.