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 & mass Increases across ---> Increases down

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