What's the deffinition of igneous rock

Igneous rocks are those rocks that were formed through cooling and solidifying the molten materials. The best example for igneous rock is solid volcanic java. Lava are liquid that comes from a volcano, but once it is dried and solidify, it becomes a rock and called igneous rock.
Another example is the granite and basalt. And according to research igneous rock comes from the latin word ignis which means fire. Thus this says it all. From a liquid becomes a rock.

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.