Presentation on theme: "Groups in the Periodic Table Another element song:"— Presentation transcript:
Groups in the Periodic Table Another element song:
The set of elements in the same column in the periodic table is a chemical group. These elements have similar physical and chemical properties. They form similar compounds when they combine with other elements. Their behaviour can be explained using Bohr-Rutherford diagrams. The key feature is the elements in a group have the same number of electrons in their outermost shell. These electrons are called VALENCE electrons. A vertical column of elements in the periodic table is called a Chemical Group. A horizontal row of elements in the periodic table is called a Period.
Alkali Metals – Group #1/1A Outer orbit has only one electron Lithium (Li), Sodium(Na), Potassium (K), Rubidium (Rb), Cesium (Cs), Francium (Fr) Shiny, silvery-grey, softer than most other metals, malleable, ductile, conduct electricity and heat Very reactive – combine with other elements easily, reacts vigorously with water to make H 2 gas Found in nature only as compounds Alkali metals can explode if they are exposed to water.
Let’ See some Alkali metals! Li - demo Na - demo K –demo What do you notice about the reaction of these? Rb Cs Fr Videos of Li to Cs Brainiac Version (3:17): Another Version(2:22): Why no Fr?(3:07):
Alkaline Earth Metals – Group #2/2A Outer orbit has 2 electrons Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), Radium (Ra) Shiny metals Reactive Form compounds that are often insoluble in water. Because of their reactivity, not found free in nature.
Halogens – Group #17/7A Outer orbit has 7 electrons. Fluorine (F), Chlorine (Cl), Bromine (Br), Iodine (I), Astatine (At) Non-metals, each has noticeable colour Very Reactive, very corrosive Found in nature as compounds Term "halogen" means "salt-former" and compounds containing halogens are called "salts“ Halogen song (3 min): Comparing 4 halogens (4 min):
Noble Gases – Group #18/8A Outer orbit of electrons is full with 8, making them stable. Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe), Radon (Rn) Gases at room temperature Odourless, colourless, tasteless Very stable and inert – they rarely form compounds If an electric current is passed through each gas, each will glow brightly (ex. Neon signs) Discharge Tube Demo Comparing 5 noble gases(1:17 min): Mythbusters Why He changes voice (0.39 min):
Hydrogen (H) (Group of one) Unique. One electron in its outer orbit – reactive. Colourless, odourless, tasteless gas Very reactive - highly flammable When reacting: sometimes it loses its electron, sometimes it gains an electron Unstable electronic structure Main element in living things, oil, coal, natural gas H Balloon Demo Hindenburg:
Metalloids Not really a group by themselves. Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), etc… zig-zag Found on the right hand side of the periodic table on either side of the zig-zag line separating metals and non-metals. Have both metallic and non- metallic properties. Some of the metalloids, such as silicon and germanium, are semi- conductors
Home Fun : 1)Read pages a) Define alloy and provide an example. b) Answer #1-5 on page 183 2)Read pages a) Answer #1, 2 on page 195