The most stable atoms are those of noble gases such as helium, neon, argon …..etc, Because their outermost energy level is filled with electrons, so, the atoms of these electrons do not undergo any...
At the beginning of the nineteenth century, Berzelius was the first scientist who classified elements into two main groups (metals and nonmetals), according to their physical properties, Indeed that was before knowing anything about...
The chemical properties & some of the physical properties of the elements depend on their electronic structure and especially on the valence electrons (the electrons of the outermost level), The concept of bond length...
The valency is the number of electrons that an atom gains, loses, or even shares during a chemical reaction, The valency is the number of electrons that an atom needs to gain or lose...
