CHAPTER 9 PERIODIC TABLE

9-1, 9-2, 9-3, 9-4, 9-6, 9-7, 9-8, 9-9

9-1 Early attempts at classification: Dobereiner and Newlands

Dobereiner discovered groups of 3 elements with similar properties that he termed a triad

Newland's Law of octaves was proposed to explain the repetition of similar properties that occurred with every 8th element when the elements were arranged in order on increasing atomic mass. BACK TO THE TOP

9-2 Mendeleev's Periodic Table

Mendeleev's predictions made his proposal seem superior to meyer's

He predicted correctly properties and masses of unknown elements

he believed that the properties of the elements were periodic functions of their atomic masses BACK TO THE TOP

9-3 Modern Periodic Law

The modern periodic law states that the properties of the elements are a periodic function of their atomic numbers

elements with similar electron configurations are listed in the same column
BACK TO THE TOP

9-4 Transition Elements

transition elements fill columns 3-12B on the table

they differ in inner shell electron filling

electrons are being added to d sublevel BACK TO THE TOP

9-6 The lanthanoids and Actinoids

elections are added to the 4f subshell in the lanthanoid series

electrons are added to the 5f subshell in the actinoid series

Periods are horizontal rows of elements

Groups are vertical columns of elements BACK TO THE TOP

9-7 The octet Rule

Eight electrons in the outer energy level of an atom represent a stable arrangement(unreactive)

first shell is full with 2(makes He stable) BACK TO THE TOP

9-8 Surveying the Table: Electron Configurations

The periodic table can be used to determine the electron figuration of an element

Atoms of the same period have the same principal quantum number

Full or 1/2 full sublevels are particularly stable BACK TO THE TOP

9-9 Metals and Nonmetals

Groups 1 & 2 contain most active metals

metals generally have fewer electrons in the outer level than nonmetals

metals are hard and shiny, conduct heat and electricity well

nonmetals are gases or brittle solids at room temperature and have dull surfaces and do not conduct electricity(insulators)

elements with 3 or fewer electrons in the outer level are considered to be metals/five or more are considered to be nonmetals.

metalloids have properties of both metal and nonmetal-on the heavy stepped line on the table!

metal character increases down the table-tends to lose electrons easier.
BACK TO THE TOP

Virtual Education, Inc A Non-Profit Education Corporation For comments, questions, suggestions or donations