1. pp. 188 - 199

2.  By the end of this lesson you should: ◦ Know how the periodic table is organized (periods vs groups) ◦ Know where the following families are located: the alkali metals, alkaline earth metals, the halogens, and the noble gases ◦ Know why families have similar properties

3.  By the late 1700’s chemists wondered why some elements existed in different states and why they reacted in different manners.  In the middle of the 1800’s the list of elements had grown to 63 and chemists still did not have a way of categorizing them.

4.  He started to categorize elements by the way they reacted; this placed all the metals on one side, and the non-metals on the other.  He was so confident in his theory that he even left gaps in the periodic table where he thought an element would be found later.

6.  The periodic table is a chart that places all of the elements in rows and columns. In the modern periodic table, elements are listed from left to right and top to bottom according to a property called atomic number.

8.  Chemists need to be able to communicate with each other throughout the world  They need an international language: Element Symbols  An element symbol is an abbreviation of the name of the element.

9.  Many of these symbols abbreviate a Latin or Greek name ◦ e.g. mercury = Hg (hydrargyrum) ◦ Sodium = Na (natrium)  A single letter symbol is always capitalized ◦ e.g. H, O, N, P  The first letter of a two-letter symbol is always capitalized ◦ e.g. Ne, He, Mg, Al, Cl

10.  The periodic table has seven horizontal rows. Each of these rows is called a period. A number written on the left side of the table identifies each period. ◦ Example: hydrogen and helium are in Period 1. Potassium is in Period 4

11.  There are 18 vertical columns in the periodic table, and each represents a different group (also called a chemical family).  The elements within a group share certain physical and chemical properties. Each group has its own number, written at the top of the periodic table. ◦ Example carbon (C) is in Group 14.

13. Alkali Metals (Group 1): Li, Na, K, Rb, Cs Similarities - All of these metals are silver-grey in colour - conduct electricity and heat - Low MP for metals - Can be cut with a knife - React with air and water

14. Differences - Gradual change in physical properties, density increases going down the group. - The elements become softer and MP decreases when moving down the table

15.  They are light, very reactive, solids at room temperature and all react with oxygen in the air.

16.  These metals have a wide variety of properties and reactivates.  They are generally hard, strong metals that conduct electricity

17.  Found in the middle-right of the periodic table  Some elements do not fit as metals or non-metals. ◦ These fit on either side of the staircase that divides the metals and the non-metals.  They have some properties of metals and some properties of non-metals.  They are called semiconductors because they do not conduct electricity well.

18. Similarities - All Non-metals - Each has a noticeable colour - all are gasses or easily form gases when heated - All are very reactive - Cl, Br, and I are used as disinfectants

19. Differences - Colours become more intense moving down the group. - MP increases moving down the group.

20. Similarities - All are gases that glow with bright colours when current is passed through them (neon light ) - None of the gases are chemically active except in special situations.

21. Differences - Density increases moving down the group - Balloons filled with the gases will rise or sink at different rates depending on their density.

22.  By the end of this lesson you should: ◦ Know how the periodic table is organized (periods vs groups) ◦ Know where the following families are located: the alkali metals, alkaline earth metals, the halogens, and the noble gases ◦ Know why families have similar properties

23.  Read pp. 188 – 199  Answer p. 204 # 1 - 12