Due to tectonic plates consistently moving I will approximately take 63.5 million years
All matter is made of tiny particles called atoms, molecules and ions; the tiny particles in solids are tightly packed and can only vibrate. The particles in liquids also vibrate but are able to move around by rolling over each other and sliding around. In gases, the particles move freely with rapid, random motion.
Beryllium has 4 electrons.
Explanation:
Atomic number , protons and electrons have the same value / their value is same .
But for the neutron there is no specific technique. You have to remember the neutrons of every element