2.2 The Periodic Table Origin Of The Periodic Table a)Chemists in the 19th century wished to...
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Transcript of 2.2 The Periodic Table Origin Of The Periodic Table a)Chemists in the 19th century wished to...
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