2.2 The Periodic Table

Origin Of The Periodic Table

a) Chemists in the 19th century wished to organize elementsb) Attempts focused on grouping elements with similar propertiesc) In 1867, Dimitri Mendeleev found patterns in the elements and organized

them into a tabled) 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 FamiliesVertical 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