Chemistry Unit 2- Period Table Trends

electronegativity

tendency of an atom to attract electrons

alkai metals

cream cheese, low melting and boiling points, make strong bases with water

alkaline earth metals

less reactive than alkai metals, relatively soft

lanthanides

high melting point, react violently with non-metals

transitions metals

malleable (wires), good conductors

actinides

row not a column

noble gases (Group 18)

colorless, odorless, tasteless, and non-reactive

halogens

nonmetals, most reactive non-metals, solids, liquids and gases

The Aufbau Rule

electrons occupy lowest energy level available

The Pauli Rule

2 electrons in the same orbital have opposite spins

The Hunds Rule

electrons in an equal energy level go in single before doubling up

atomic radius

distance of 2 nuclei and divided by 2

Mendeleev

organized the period table by atomic radius

Moseley

organized the periodic table by atomic number