Which orbital is the first to be filled in an atom

It has a complete energy level and does not want to gain or lose any electrons. The helium atom is not reactive. In fact, helium is the first of a group of elements often referred to as the inert or noble gases. With so many orbitals, you may be wondering how to write the description of an element with all its orbitals. It's time to talk notation styles.

It's Elementary : Orbitals. Tool: Interactive Periodic Table. The P Orbital Once the s orbital has been filled for any energy level, electrons start filling in the next higher orbital "style" -- the p orbital. The p orbitals are shaped like propeller blades, with one set lined up along the x axis of the atom horizontally.

A second p orbital is lined up along the y axis of the atom vertically. The third and final p orbital is lined up along the z axis from front to back through the atom. This makes a total of three p orbitals to be filled in any given energy level from the second up. Each of these three p orbitals needs to be filled with electrons in the second and higher energy levels. But there is another rule to follow in placing the electrons in the p orbitals. This is Hund's Rule. Hund's rule states that each p orbital must receive one electron before any p orbital can receive a second filling electron.

You could think of this as the good mother rule. Everybody gets one before anybody gets seconds. Filling the Orbitals Let's try a sample filling of electrons in p orbitals. To do this we will have to go all the way over to element number five, boron. If you still need more review, the theory was presented in Kotz Chapter 7.

So now that we have reminded ourselves about the orbitals and how the electrons fill them, we need to address how these orbitals interact when two or more atoms bond together. Principle energy level n. Number of orbitals per type. Number of orbitals per level n2. Half-filled and filled subshells are especially stable, leading to some anomalous electron configurations:. In the case of chromium, an electron from the 4 s orbital moves into a 3 d orbital, allowing each of the five 3 d orbitals to have one electron, making a half-filled set of orbitals.

In the case of copper, silver and gold, an electron from the highest-occupied s orbital moves into the d orbitals, thus filling the d subshell. Many anomalous electron configurations occur in the heavier transition metals and inner transition metals, where the energy differences between the s , d , and f subshells is very small. Key: s-block p-block d-block f-block. Predicted configuration.