The answer is 
. A magnesium atom has 12 protons and an arrangement of [2, 8, 2]. When you lose two electrons, arrangement becomes [2,8] and the atom becomes a positively charged ion
Ok, my favorite is turning lights off when not in use OR changing out old lightbulbs that are more efficient. :)
Because flame provides a source of heat so that the magnesium metal atoms can overcome their activation energy. Activation energy is the minimum energy required in order for a chemical reaction to proceed. When the magnesium metal burns it reacts with oxygen found in the air to form Magnesium Oxide.
The difference between short period and long period is based upon the number of elements in each period. Shortest period is the first period which contains elements, while the longest period is the 6th period which contains 32 elements.
