It would have 20 protons, 20 neutrons, and 20 electrons. Protons and electrons are USUALLY (I say usually because of the different types of atoms) the same as the atomic number. To find neutrons you take the atomic mass minus the atomic number. 40-20=20
Answer:
Universe
Explanation:
This should go to physics category
The big bang theory is derived from the observed universe, and the microwave background signal that arrived to earth...
It is a to my knowledge, but I will give an update when i find out
Organism-population-community-ecosystem-biome in that order