Periodic Trends

? Atomic Radius (Size) What’s the trend? Decreases across a period due to increase in positive nuclear charge Increases down a group due to increasing number of energy levels (shells)

Ionic Radius (size of ions) Ion: an atom that has a positive charge (cation) or negative charge (anion) Cations have a smaller ionic radius than corresponding atom Protons outnumber electrons Less shielding of electrons Anions have a larger ionic radius than corresponding atom Electrons outnumber protons Greater electron-electron repulsion

Ionization Energy The energy required to remove one electron from a neutral atom of an element (kj/mol) (form a cation) Energy must be added to remove an electron to break the attractive forces between the electron and the protons in the nucleus The easier it is to remove an electron, the smaller the ionization energy Atoms with multiple electrons have multiple Ionization Energies Ionization Energy increases for each successive electron First Ionization Energy < Second Ionization Energy <Third…

Ionization Energy Whats the trend?

Ionization Energy IE tends to increase across each period. Atoms are getting smaller, electrons are closer to the nucleus IE tends to decrease down a group Atoms are getting larger, electrons are farther from the nucleus Outer electrons becomes increasingly more shielded from the nucleus by inner electrons Metals have characteristically low IE Nonmentals have high IE Noble gases have a very high IE

Electron Affinity The change in energy that occurs when an electron is added to a gaseous atom (An Anion is formed) The easier it is to add an electron, the higher the electron affinity Electron Affinity decreases as you add more electrons First EA > Second EA > Third EA…

Electron Affinity – What’s the trend Electron Affinity – What’s the trend? Where on the periodic table is EA the least? Is it the most? Halogens have the highest electron affinities Metals have low electron affinities Affinity tends to increase across a period and decrease down a group

Electronegativity Electronegativity