Periodic Trends

Jon Beacher Periodic Trends The periodic table has eight periodic trends which include acidity, atomic radius, ionization potential, electron affinity, electro-negativity, metallic character, nuclear charge and shielding. First, the acidity of every element increases when going left to right on the periodic table. The atoms on the right seem to attract electrons better than those on the left, so this leaves the left ones more basic and the right ones more acidic. The acidity decreases going down the periodic table. Second, the atomic radius tends to decrease as one goes across a period because the nuclear charge increases, and therefore attracts the orbiting electrons surrounding the radius. The atomic radius also increases as it descends down a group. It does this because the energy shell increases spurring the outer electrons to go further away form the nucleus. This increases the atomic size, however; the amount of protons has a bigger effect than the radius. Third is Ionization potential. Ionization potential (/energy) is the amount of energy required to remove one of its electrons. Ionization potentials tend to increase while on progresses across a period because of the greater number of protons attract the orbiting electrons stronger, so it increases the energy that is required to remove one of the electrons. As an element goes down the periodic table, its iodization energy decreases because it requires less energy to move them. The fourth periodic trend is electronic affinity. Electronic affinity is the energy required to remove an electron from a singly charged ion. As an element goes across a period, the electronic affinity will increase due to the bigger attraction from the nucleus and the atom attraction the electron as it reached maximum stability. If you go down a group, the electron affinity increases because of a large increase in the atomic radius. Another periodic trend is electro-negativity. This is the measure of the ability of an atom or molecule to attract electrons into a chemical bond. The type of bond formed is determined by the difference of the electomagnetivity of the atoms. When going down a group, the electromagnevity decreases because the atoms have less of attractions for electrons or protons. Metallic character is the fifth periodic trend. This refers to the chemical properties associated with elements classified as metals. The properties come from the element’s ability to lose electrons are called the thermite process. As an element goes across a period from left to right in the periodic table, the metallic character decreases as the atoms are more likely to gain valence electrons than lose them. When you go down a group, the metallic character increases because to the lesser attraction from the nucleus. Sixth, there is nuclear charge. This increases going top to bottom and left to right across the periodic table. This is due to the increase in nuclear charge. Nuclear charge is equal to the difference in the elements between the element and the first element in the period. Lastly is shielding. Shielding of outer level electrons goes up as you go down the groups on the periodic table. This is because there are extra levels of electrons between the outer electrons and the nucleus. It does not increase when you go side to side because there are no extra levels of electrons.