Final answer:
The modern periodic table arranges elements into groups based on their valency, electronic configuration, and classification as metals, nonmetals, or semimetals. Elements in the same group have similar valence electrons and valency. Electronic configurations affect chemical properties, while the location within the table classifies the element's type.
Step-by-step explanation:
The modern periodic table is a chart where elements are arranged in order of increasing atomic number in rows called periods and columns known as groups or families. In terms of valency, elements in the same group typically have the same number of valence electrons and thus similar valency. For example, elements in Group 1 have one valence electron and commonly exhibit a valency of +1, whereas elements in Group 17 have seven valence electrons and typically exhibit a valency of -1.
The electronic configuration of an element refers to the distribution of electrons in its atomic orbitals. Elements in a group have a similar outer electronic configuration, which accounts for their similar properties. For instance, alkali metals in Group 1 have an outer electronic configuration of 's1', whereas halogens in Group 17 have 's2p5' as their configuration in the outermost shell.
The modern periodic table also classifies elements into metals, nonmetals, and semimetals (or metalloids). Metals are situated on the left side of the periodic table and are characterized as lustrous, good conductors of electricity, and malleable. Nonmetals are placed on the upper right hand of the table, showing opposite characteristics to metals. Semimetals are located between metals and nonmetals and exhibit properties that are intermediate between the two.