The chemical properties of an element are determined by the electrons in the partly filled outermost shell. This shell is referred to as the valence shell. There are one or more subshells in each shell, and each subshell is made up of one or more atomic orbitals.
An element is a substance made exclusively from one type of atom and which cannot be broken down further into smaller particles by nonchemical reaction. An element is identified by the number of protons contained in the nuclei of its atoms. All the elements are listed in the periodic table with such details as chemical symbols. An element’s positioning in the periodic table is essentially determined by the number of electrons, the group is determined by the number of valence shell, and the elements block is determined by the type of orbital in which the valence electron is located.
Chemical properties of elements in the periodic table include atomic number, atomic mass and electronegativity. The atomic number refers to the number of protons contained in the core of an atom. The atomic mass is the mass of an atom presented as atomic mass units. Electronegativity indicates the affinity of an atom to attract electrons from another atom to its side during a chemical bonding. Other chemical properties include density, melting point, boiling point, van der Waals radius, ionic radius and isotopes.