![]() ![]() For a many-electron atom, the energy required for the reaction:energy + X (g) → X + (g) + e -is called the first ionization energy (I 1 ). The higher the ionization energy, the more difficult it is to removethe electron. This is related to how "tightly" the electron is held bythe nucleus. The best shielding comes from s orbitals, followed by p, d and f.Ionization EnergyIonization energy is the energy required to remove an electron from a gaseousatom in its ground state. The sorbitals are said to be penetrating - they have electron density close to thenucleus. Going across arow generally leads to a stronger interaction between the nucleus and thevalence electrons.The type of orbital holding the shielding electrons is also important. There is also an increase in the number of valence electrons,but electrons in the same shell are poor at shielding each other. This leads to better shielding and a weaker attractionbetween the nucleus and the outer shell electrons.Going across a period leads to a larger nuclear charge, as the number ofprotons increases. ![]() Going down a group increases the value of n, and increases the number ofinner shell electrons. The charge felt by the valenceelectrons is called the effective nuclear charge, Z eff. As the number of electrons between the nucleus and the valenceelectrons increases, the apparent nuclear charge decreases, due to the"screening" of these inner shell electrons. #Periodic table chemistry worksheet full#Electrons are held in the atom by theirelectrostatic attraction to the positively charged protons, the nuclear charge, Z.However, not all electrons in an atom experience the same nuclear charge.Those closest to the nucleus experience the full nuclear charge and are heldmost strongly. Among these properties are IonizationEnergy, Electron Affinity and Atomic/ Ionic Radii.These properties all involve the outer shell (valence) electrons as well as theinner shell (shielding) electrons. Worksheet 12 - Periodic TrendsA number of physical and chemical properties of elements can be predicted fromtheir position in the Periodic Table. ![]()
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