Each atom of magnesium contains twelve protons.
More Info: This information is readily available in any periodic table via the atomic number. The atomic number is also known as the proton number because it is equal to the number of protons in an element's nucleus; magnesium's atomic number is twelve.
Protons Remain Consistent
All elements always have the same number of protons, but confusion may arise from varying weights and charges on different compounds. For example, although magnesium has nine electrons when neutrally charged, in nature it is often found with only ten. The number of neutrons in an element also may vary, leading to confusion about the number of protons. The number of protons in an atom of any element never changes, however, because elements are defined by the number of protons per atom.
Magnesium Is a Reactive Metal
Magnesium is a highly reactive alkaline earth metal. The reactivity is due to its tendency to oxidize, or give up electrons. This reactivity can be observed by igniting a rod of magnesium and observing the extremely bright white flame emitted. In fact, it was this tendency to burn at extremely high temperatures (reaching over 5000 degrees Fahrenheit) that led to magnesium's use in the firebombing of Europe during World War II. Today, magnesium is commonly as an alloy in structures or as a pure element in high performance automobiles. The pure form of magnesium is similar in quality to aluminum. Due to its low weight and high strength, magnesium is increasingly being used in the production of modern aircraft.