The outermost orbital shell of an atom is called its valence shell, and the electrons in the valence shell are valence electrons. Valence electrons are the highest energy electrons in an atom and are therefore the most reactive.
Are s orbitals valence electrons?
Fill the orbitals of the atom in the order 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p and 5s. Each s orbital can hold two electrons, each p orbital can hold six electrons and each d orbital can hold 10 electrons. Discern which s or p orbital filled last. These orbitals contain the valence electrons for the element.
How many valence electrons does the p orbital have?
According to the periodic table above, phosphorus belongs to Group 5A. Therefore, Its valence electrons should be 5. The outermost orbitals, 3s2 3p3 , contains 5 electrons. Thus, valence electrons for P is 5.