Periodic Trends

Definitions

& Trends

ELECTRONEGTIVITY

Electronegativity is the power of an atom, when in a molecule, to attract electrons to itself.

Electronegtivity Increase across --->Decrease down

ATOMIC RADII

1/2 the distance between the nuclei two like atoms

Different Atomic Radii

Atomic Radii decrease across ------> increase down

IONIC RADII

The radius of an atom after it has gained or lost an electron and becomes an ion

Ionic Radii Increase Across ---->Increase Down

IONIZATION ENERGY

energy necessary to remove an electron from the neutral atom.

Ionization Energy Increase Across ---->Decrease down

ELECTRON AFFINITY

is a measure of the energy change when an electron is added to a neutral atom to form a negative ion.

Electron Affinity Increase Across ---->Decrease Down

Electron Shielding

The effects of the inner electron shell on the outer most electrons

Increase Down Generally decreases across

Atomic Number & Mass

Atomic Number is the number of protons in an element

Atomic mass is the relative average mass of an element

Atomic number & massIncreases across --->Increases down

Melting and Boiling Point

Generally increase across the chart until d orbitals become half filled then Mp and Bp decrease