GO 3 Describe ideas used in interpreting the chemical nature of matter, both in the past and present, and identify example evidence that has contributed to the development of these ideas 3-3 The Periodic Table

Guided Question What is the periodic table of elements? And how is it organized?

Mendeleev A picture of Mendeleev’s Original Periodic table and the scientist himself!

1869 – Dmitri Mendeleev Organized the 63 known elements into a series of rows and columns based on physical and chemical properties He left gaps in the table explaining there were elements that had not been discovered yet He then hypothesized about the physical and chemical properties of the atoms that would fill the voids After his table was published, gallium was discovered and with properties almost exactly the same as Mendeleev predicted, it fit in an open space!

Breaking Down the Element

Indicates number of Protons in the nucleus & number of electrons orbiting

Understanding the Periodic Table Understanding the Periodic Table Need to know: Metals are Yellow Non-metals are green Metalliods are purple

Metals vs. Non-metals ___

OR vs

Metals Grouped on the Right side of the periodic table (88 of the elements are metals) Physical Properties: Shiny solids at room temperature High conductors of heat and electricity Ductile (can be formed into wires) Malleable (rolled and can be beaten into thin sheets)

Non-metals Grouped on the right side of the periodic table Physical Properties: May be solid, liquid or gas at RT Poor conductors of heat and electricity (called Insulators) Solid forms are dull and brittle

Metalloids have both metallic and non-metallic properties TelluriumSilicon

Understanding the Periodic Table Each horizontal version is called a PERIOD (1 to 7) Each Vertical column forms a group (or FAMILY) (1-18)

Understanding the Periodic Table Need to know: Group 1 Group 2 Group 17 Group 18

____ Metals – Group 1

Alkali Metals – Group 1 The most reactive of the metals They react when exposed to air or water As you move down the group, reactivity increases. Lithium Sodium Cesium

Alkaline Earth Metals – Group 2

They react when exposed to air or water but not as strong as that of the alkali metals

Halogens– Group 17

The most reactive non-metals (Fluorine can etch glass) Can combine with other elements to form new substances; Ex: Na +F = sodium fluoride found in Toothpaste Various colors and physical states F and Cl = yellowish green gas; Br = dark red liquid; I = purple-black solid with a metallic crystalline sheen

Inert Gases – Group 18

Also known as the NOBEL GASES The most Stable and unreactive elements; long thought that they could not combine with other elements 1962 – Canadian Chemistry Neil Bartlett (B.C.) was the first to prepare a compound containing a noble gas (XeF 4 )

What is the deal with

Hydrogen Considered to be a Non metal element (Sometimes has a special or separate spot on some versions of the Periodic Table) Here are basic facts about the Hydrogen element in the periodic table: Is the most abundant element in the universe (75% of everything is H) Hydrogen gas is extremely flammable (The Hindenburg) Is a colourless and odourless gas at room temp Can take on a negative charge (H-) or a positive charge (H+) Hydrogen is the lightest of all elements - atomic mass