2.2 The Periodic Table Origin Of The Periodic Table a)Chemists in the 19th century wished to organize elements b)Attempts focused on grouping elements with similar properties c)In 1867, Dimitri Mendeleev found patterns in the elements and organized them into a table d)The resulting table had holes for elements not yet discovered Let’s take a look at the very first attempts of organizing the periodic table …some look soooo different to today’s periodic table!

Early symbols

Meyer's Spiral periodic table of 1872

1886 Crookes' Periodic Table

Our modern Periodic Table

THE MODERN PERIODIC TABLE Organized according to ATOMIC number --- by Mendeleev The properties of the elements repeat/recur periodically when the elements are arranged in increasing order by their atomic numbers

Our modern Periodic Table The Periodic Table provides information on the physical and chemical properties of elements Atomic Mass - mass of average atom Atomic Number - number of protons Ion Charge - electric charge that forms when an atom gains or loses electrons

Trends in the Periodic Table: The periodic table organizes the elements by vertical columns (___________) and horizontal rows (______________). The elements are arranged depending on the chemical and physical properties of elements in repeated patterns and increasing atomic masses.

THE PERIODIC TABLE

Metals, Non-metals, Metalloids See page 55

Periods and Families 1)Each horizontal row in the periodic table is a period 2)Vertical columns form groups or chemical families

Zoom in on Families Vertical columns form groups or chemical families a) Alkali metals - highly reactive group 1 metals b) Alkaline earth metals - group 2, burn in air if heated, reactive metals c) Halogens - group 17, highly reactive non-metals d) Noble gases - group 18, stable and unreactive non-metals

Try: For Sulphur, give the following information: Atomic number: Average atomic mass: Ion charge: Symbol of element: Protons?

Homework: Worksheet 2.2