The periodic table is arranged by various patterns. Identify two patterns and give examples of both patterns
Two common patterns seen in the arrangement of the periodic table are:
1. Periodic Pattern: Elements are arranged in periods or rows based on their increasing atomic number. Each period in the periodic table corresponds to the filling of a new energy level or shell. For example, the first period (Period 1) consists of only two elements, hydrogen (H) and helium (He), filling the 1s orbital. The second period (Period 2) contains eight elements, from lithium (Li) to neon (Ne), filling the 2s and 2p orbitals.
2. Group or Family Pattern: Elements are also arranged in groups or columns that share similar properties. Elements within the same group have similar valence electron configurations and exhibit similar chemical behavior. For example, Group 1 (also known as the alkali metals) consists of lithium (Li), sodium (Na), potassium (K), and so on, all of which have one valence electron and react vigorously with water. Similarly, Group 17 (also known as the halogens) comprises fluorine (F), chlorine (Cl), bromine (Br), and iodine (I), which are all highly reactive nonmetals.