VIDEO: P.T. Intro and Periodic Table Trends

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Periodic Tables

1. Ionization Energy Trend- Increases along a period and up a group.

Why? Since the mass of the nucleus is increasing, the force pulling on the electrons is greater, making a more tightly bound atom making it much more difficult to remove an electron. However, due to increasing the number of electron shells as you move down a particular group, it becomes easier to remove an electron, which is reflected by the decrease in the ionization energy. This is perhaps the simplest of the periodic table trends to remember.

2. Electronegativity Trend- The definition of electronegativity is the tendency of an atom to attract electrons. It follows the same periodic trend as ionization energy--increases along a period and up a group.

3. Metallic Character Trend- First, what is metallic character? It is the attribute of an atom to lose an electron to form a cation. This phenomenon decreases along a period and up a group because of the weaker attraction between nucleus and electron. What we see here is the opposite of the electronegativity and ionization energy trends in the periodic table.

4. Atomic Radius Trend - Radii decrease along a period because the increasing mass of the nucleus pulls the electrons inward with greater force, shrinking the overall diameter of the atom. Atomic Radius decreases as you move up a group due to the decreasing size of the electron cloud.

5. Electron Affinity Trend- Electron Affinity is defined as the energy released when a neutral gas state atom gains an electron, making it ionized. This amount of energy increases along a period and up a group; the same trend associated with electronegativity and ionization energy.This is the most difficult of the 5 periodic table trends to conceptualize.

5 Trends of the periodic table