The Trend on a GraphĪs shown in the graph below, the atomic radius is largest at the first element in each period, and it decreases down each period. As electron cloud sizes increase, so do atomic radii. This is because between each group, electrons occupy successively higher energy levels. Group Trendĭown a group, atomic radii increase. This is why the difference in atomic radii decreases down each period. One thing to note is that the effect of the attraction between the positively charged nucleus and the electrons is slightly countered by the repulsion of electrons as they are successively added. This increased positive charge attracts or pulls, the electrons in closer to the nucleus, decreasing the atomic radius. Down the period, however, the number of protons also increases. If the atom has a smaller atomic radius, it means the electrons are being pulled close to its nucleus much more (generally) Because of this, Flourine for example would be an electron 'hog'- it is the most electronegative element on the periodic table and will gladly take away and hold onto an electron. This is because while the number of electrons increases down the period, they only add to the same main energy level, and therefore do not expand the electron cloud. For example, ionization energy, electronegativity, and of course atomic radius which we will discuss now. There are many trends on the periodic table. Let’s break down the trend into its period and group trends. Atoms decrease in size across the period and increase in size down the group. Atomic Radius Trend on the Periodic TableĪtomic radii increase toward the bottom left corner of the periodic table, with Francium having the largest atomic radius.

Thus the atomic radius is measured as shown in the diagram below.

This is because the borders of orbitals are quite fuzzy, and they also change under different conditions. While your initial thought may have been to measure the distance from the center of an atom’s nucleus to the edge of its electron cloud, this is inaccurate and not feasible. Therefore, the atomic radius of an atom is typically measured as half the bond length between two identical atoms. On the periodic table, atomic radius generally decreases as you move from left to right across a period (due to increasing nuclear charge) and increases as you. The atomic radius is measured as half the distance between two nuclei of the same atoms that are bonded together. This is caused by the increase in the number of protons and. Let’s discuss the definition of the atomic radius, also called atomic size, and the atomic radius trend on the periodic table. Atomic radius decreases from left to right within a period.

Atomic radius periodic trend