Periodic Trends

Ionization Potential

Atomic Emissions

Electron Affinity Electronegativity

Metallic character

Atomic Radius

Ionization Energy

Ionization energy is the energy required to move one electron from an atom.

Ionization energy increases as you move across the periodic table from group 1 to group 8 and decreases as you move down the periodic table from period 1 to period 7.

Ionization energy increases across a period because the greater number of protons (given by the atomic number) attract the orbiting electron more strongly, thereby increasing the energy required to remove one of the electrons.

Ionization energy decreases down a group because the valence electrons are further away from the nucleus and therefore experience a weaker attraction to it.

Ionization Energy

Electron AffinityElectron affinity is the energy required to detach

an electron from a singly-charged anion.Electron affinity increases as you move across

the periodic table from group 1 to group 8 and decreases as you move down the periodic table from period 1 to period 7.

Electron affinity increases across a period because of the larger attraction from the nucleus and the atom wanting the electron more as it reaches maximum stability.

Electron affinity decreases down a group because of the large increase in the atomic radius.

Electron Affinity

Metallic CharacterMetals tend to beBe shiny, lustrous, and malleableBe good conductors of both heat and electricityHave low ionization energies (so they commonly for

cations)Form ionic compounds with chlorine (metal chlorides)Form basic, ionic compounds with oxygen (metal

oxides)

Metallic character -decreases as you move across the periodic table from

group 1 to group 8 -increases as you move down the periodic table from

period 1 to period 7

Metallic Character

Atomic EmissionsIs the emission of radiation as

electrons of an atom move from excited state to ground state

As a result of the electron transition there is visible emission on a spectrum

The gap in energy between the initial and final state determines the wavelength of light emitted

ElectronegativityElectronegativity is the chemical property that

describes how well an atom or molecule attracts electrons and therefore tends to become a negative ion. The higher the electronegativity, the more it attracts electrons. Electronegativity is shown as a dimensionless quantity running from approximately 0.7 to 3.98. Generally, as you move across the periodic table from group 1 to group 8, electronegativity increases and as you move down the periodic table from period 1 to period 7, electrongativity decreases.

Electronegativity

Atomic RadiusThe atomic radius of an atom is the average

distance from the nucleus of the atom to the boundary of the electron cloud. The concept is generally difficult to define because electrons do not have definite orbits and have conceptual positions around the atom’s nucleus. Atomic radius is measured in picometers (1x10-12m) and most elements fall in the range of 30-300 pm. Generally, as you move across the periodic table from group 1 to group 8, atomic radius decreases and as you move down the periodic table from period 1 to period 7, atomic radius increases.

Atomic Radius