Electrons revolve in shells around the nucleus of the atom.
The nucleus contains protons and neutrons. Protons are positively charged sub-atomic particles and neutrons are neutrally charged.
The number of electrons in an atom largely decides the properties of the atom.
The radius of the electron is 2.82 x m. It has a radius 2.5 times larger than a proton.
The charge of the electron is -1.602 x Coulomb.
The number of filled electron shells increases as moving down a group in the periodic table.
The valence electrons keep the same effective nuclear charge in a group but the orbitals are farther from the nucleus. Therefore, the nucleus has less of a pull on the outer electrons, and the atomic radii are larger.
Ionization Energy and electronegativity increases as one goes from left to right in a periodic table, and Ionization Energy and electronegativity decreases as one goes from top to down in a periodic table.