Volcano ! *i give ! *
a volcanic occurs when the in a magma becomes so great it is released like a valve. magma is released through the volcano's in an eruption of rocks (bombs) and ash.
a volcanic develops over centuries as flowing from the active volcano to form layers of rock

A volcanic eruption occurs when the pressure  in a magma chamber becomes so great it is released like a valve. Magma is released through the volcano's cone in an eruption of lava rocks (bombs) and ash. A volcanic cone develops over centuries as flowing lava from the active volcano cools to form layers of rock. 
Hope this works,
Ahawk

All the elements are arranged by melting points on the periodic table. in row they go from metals to gasses. in the row from sodium to argon, sodium is more reactive than the one on its right, magnesium.