Modern Periodic Table

The fundamental principle stating that physical

The fundamental principle stating that physical and chemical properties of elements are periodic functions of their atomic numbers (not atomic mass as

The modern periodic table contains 118

The modern periodic table contains 118 elements arranged in 7 horizontal periods and 18 vertical groups. Periods represent electron shells (n = 1 to 7

Element position in the periodic table

Element position in the periodic table directly correlates with electronic configuration. Period number equals the principal quantum number (n) of out

The net positive charge experienced by

The net positive charge experienced by valence electrons after accounting for shielding by inner electrons. Zeff = Z - σ (where Z = nuclear charge, σ

Atomic radius decreases across a period

Atomic radius decreases across a period (increasing Zeff) and increases down a group (additional electron shells). Cations are smaller than parent ato