The orbital box diagrams are listed for the first 20 elements in the figure below. Boxes, or horizontal lines represent the orbitals, arrows represent the electrons, and if an orbital is full, the electrons must be of opposite spinвЂ“one arrow pointing up and the other one pointing down. An orbital box diagram can be written as well.

The electron configuration for carbon is 1s 22s 22p 2.

Reading the periodic table from left to right, the boron atom has 5 electrons, and the electron configuration is 1s 22s 22p 1. The four electrons of Be go into the 1s and the 2s orbitals giving the electron configuration of 1s 22s 2. Next we go to lithium with 3 electrons two of the electrons go into the 1s orbital and the third electron into the 2s orbital giving an electron configuration of 1s 22s 1. Helium has 2 electrons and both electrons go into the 1s orbital and the electron configuration is 1s 2. Hydrogen has 1 electron which goes into the 1s subshell. You only need to know where the blocks are located on the periodic table. When reading the periodic table from left to right, one can easily write an electron configuration without memorizing the filling order. The periodic table below, shows the s, p, d, and f-blocks. The filling order follows:ДЎsв†’2sв†’2pв†’3sв†’3pв†’4sв†’3dв†’4pв†’5sв†’4dв†’5pв†’6sв†’4fв†’5dв†’6pв†’7sв†’5fв†’6dв†’7pД®lectron configurations and orbital box diagrams can be written right from the periodic table. For example the 1s orbital is filled and then we can fill the 2s orbital and go on to the 2p orbitals. The lowest energy orbitals must be filled first. In other words, the orbitals in a subshell must be half filled before pairing electrons. HundвЂ™s Rule specifies that when orbitals of equal energy are available, the lowest energy electron configuration has the maximum number of unpaired electrons with parallel spins. The Pauli Exclusion Principle states that each orbital may contain a maximum of 2 electrons electrons must have opposite spins.ДЈ. The Aufbau Principle states that electrons are always placed in the lowest energy sublevel that is available.Дў.

Teachers: Please review the Instructor's Guide for tips on implementing this simulation in the classroom.1. If you are using this learning object as part of a class your teacher may ask you to complete the companion Worksheet.

Predict the correct electron configuration from the atom's position on the periodic table.

Connect the correct electron configuration with the lowest energy for the atom.

Arrange the electrons in an atom to obtain the correct electron configuration.

Upon completion of this interactive learning object, students will be able to: Each box on the energy ladder represents an atomic orbital that can contain 0, 1, or 2 electrons. The Energy Ladder is a graphical representation of an atom's electron configuration in which the orbitals are arranged vertically in the order of their relative energy levels. Your task is to discover what the ground state electron configurations are вЂ“ and how these can be predicted from the periodic table.

The вЂњground stateвЂќ electron configuration is the lowest energy combination of electrons in the atomic orbitals. The electron configuration is a listing of which atomic orbitals are occupied by electrons, and how many electrons are in each type of atomic orbital.

Helium electron configuration