What diagram is used to remember the order in which energy levels and sublevels are filled?

The diagonal rule is a mnemonic device used to determine the order in which atomic orbitals are filled with electrons. It is based on the principle of increasing energy levels, allowing students to visualize how electrons occupy sublevels in a systematic way. The rule outlines a specific path—when you follow the diagonal arrows in the periodic table, you can identify the filling order: from the lower energy orbital to the higher energy ones.

This is crucial for understanding the configuration of electrons in atoms, as it directly relates to their chemical properties and the periodic trends observed in elements. By using the diagonal rule, students can remember that the 1s sublevel fills first, followed by 2s, then 2p, 3s, and so on, following the diagonal layout until all orbitals in the relevant energy levels are filled.

In contrast, the other options serve different purposes in chemistry. For example, a flame test identifies elements based on the color they emit when heated, while an orbital diagram visually represents the arrangement of electrons within orbitals but does not specifically provide a sequence for filling them. Lewis structures are used to illustrate the bonding between atoms and the arrangement of electrons in molecules, which does not pertain to the filling of energy levels and sub