Periodic Trends Atomic Radii Defined by the edge

Periodic Trends

Atomic Radii • Defined by the edge of its orbital but since the edges are fuzzy, difficult to determine • Atomic Radii – half the distance between the nuclei of identical atoms that are bonded together

Atomic/Ionic Radii

Arrange the following groups in order of increasing atomic size: • Rb, Na, Be • Sr, Se, Ne • Fe, P, O

Ionization Energy • An electron can be removed from an atom if enough energy is used • Ionization energy – the energy required to remove one electron from a gaseous neutral atom A + energy A+ + e-

Ionization Energy

Ionization Energy

Arrange the following groups in order of increasing first ionization energy: • Rb, Na, Be • Sr, Se, Ne • Fe, P, O

Electron Affinity – the energy change when an electron is added to a gaseous neutral atom, exothermic process A + e- A- + energy

Electron Affinity

Order the atoms in each of the following sets from the least exothermic electron affinity to the most. • N, O, F • Al, Si, P

Electronegativity • applies when an atom is in a compound NOT alone • Electronegativity – measure of how strongly an atom attracts electrons when it is in a compound • Fluorine (the most electronegative element) is assigned a 4. 0 and then all the others were determined by comparison

Electronegativity

Predict some of the properties of element 117 (Uus): • What will be its electron configuration? • What element will it resemble most chemically? • What will be the formula of the neutral binary compounds it forms with sodium, magnesium, carbon, and oxygen?