The number of valence electrons that an atom has is a very important factor in determining its chemical properties. An atom with a lot of valence electrons is less reactive than an atom that has fewer valence electrons.
When an atom is formed, the outermost electrons, or valence electrons, are added to the atom. These are the electrons that are responsible for forming chemical bonds.
They also make up the outermost shell of an atom, generally a group of 2 or 8. From a chemical bonding perspective, it is preferable for atoms and molecules to have their valence shells filled.
Besides their importance for chemistry, valence electrons also determine how an atom reacts with other atoms. For example, metals will commonly lose their valence electrons when they bond with other atoms.
If a valence electron is lost, the atom will form a negative charge. This negative charge is called a cation, and antimony will form either Sb3+ or Sb5+ ions.
The orbital diagram for antimony shows that it has two electrons in its first shell, eight electrons in its second shell and eighteen electrons in its third shell.
In order to know how many valence electrons an atom has, we must first figure out the full electron configuration of the element. This is done by calculating the atomic number and identifying the appropriate orbitals for the atom.
Then, we calculate the energy of each orbital using Hund's principle and Bohr's formula. The orbital with the lowest energy is the one that the electron will enter first, and it will be shifted gradually to a higher energy orbital as the electron gains more energy from its surroundings.
