Periodic Table and Chemical Properties Science 9

Objectives Describe the history of the periodic table Know the type of information that can be found on the periodic table Understand the difference between Metals, Non-metals and Metalloids

Origin of Periodic Table 19th century chemists wanted to organize their observations of the elements Wanted to group elements with similar properties together 1867 Dmitri Mendeleev made a card for every known element He included density, colour, melting & boiling point He used these cards to sort and re-sort until he found a pattern

Origin of Periodic Table Many scientists were trying to organize the elements Mendeleev was successful since he realized there needed to be holes left for undiscovered elements Mendeleev was able to predict the properties of elements that were later discovered from the placement of the holes and the surrounding known elements

Information on Periodic Table Periodic Table contains a lot of information Name Symbol Atomic number Atomic mass Ion charge

Periodic Table – Symbol and Name Symbol is generally the largest piece of information Name is usually written underneath of the symbol

Periodic Table – Atomic Number Atomic number = the number of protons It is always a whole number (not a decimal or fraction) Pattern? starts at number 1 and increases in a regular way down the table

Periodic Table – Atomic Mass Mass of average atom of an element Measured in atomic mass units (amu) Pattern? Tends to increase along with atomic number *exceptions do occur ex. Cobalt and Nickel

Periodic Table – Ion Charge Ion charge – electrical charge that forms on an atom when it gains or loses electrons Some elements have multiple ion charges Pattern? Elements on right side of table generally positive. Elements on the right hand side are generally negative

Metals, Non-metals and Metalloids Elements can be categorized into three groups 1. Metals 2. Non-metals 3. Metalloids

Metals, Non-metals and Metalloids Metals: typically hard, shiny, malleable, ductile, and good conductors of heat and electricity Non-metals: Do not have the above properties, generally gases or brittle solids at room temperature Metalloids: elements that share some properties with metals and some properties with non-metals

Metals, Non-metals and Metalloids

Metals, Non-metals and Metalloids The Periodic table is organized so elements with similar properties are grouped together. Where are the metals located? Where are the non-metals located

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Metals, Non-metals and Metalloids Staircase line starting next to Boron Metals are on the left side of this line Non-metals (except for Hydrogen) are located on the right side of this line Metalloids are elements whose box shares a border with the staircase line is a metalloid.