thermochem

Atomic Radius (across a period)

atomic number increases due to increasein proton in nucleus (increase in charge in nucleus/) - electrons are added to the same energy level so no additional shielding, and no increase in distance from the radius. therefoer there is increased electrostatic atttractino between the increasing charge of nucleus and negative valence electrons (they are pulled closer to the radius therefore decreases

atomic radius (down a group)

atomic number increases due to the increase in protons in nucleus and the increase in charge in nucleus. Valence electrons are in energy levels that are further from the nucleus. the innter energy levels also provide additional shielding of valence electrons from nucleus. therefore there is decreased electrostatic attration between nucleus and valence electrons, so atomic radius increases down a group

ionic radius - cations

cations lose their valence electron, causing an energy level to be lost. valence electrons are closer to nucleus, greater electrostatic attraction between nucleus and valence electrons, smaller radius.

ionic radius (anions)

anions gain an electron, increases reupulation between the valence electrons. This makes the electrons further from the nucleus resulting in weaker attractive forces. Therefore ionic radii of anions are usually greater than the atomic radius for that element

first ionization energy definition

the minimum energy required to remove one electron from each atom from a mole of atoms in the gaseous state

ionization energy (across a period):

atomic number increases as more protons are added to the nucleus. Electrons are added to the same energy level iwth no additional shielding. increases as the attractions between the nucleus and valence electrons increase and repulsion decreases, therefore more energy is required to remove valence electrons

ionisation energy down a group

valence electron lost is further away from the nuvleus as you go down a group. There is also additional shielding of the valence electron by the extra inner shells of electrons.

decreases down a group as attractions decrease and repulsion increases, therefore less energy is required to remove valence electrons.

exceptions

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