Presentation on theme: "Groups in the Periodic Table. Metal, Non-metal, or Metalloid? Colour or write in the metals, non-metals, and metalloids. Be sure to classify every element."— Presentation transcript:
Metal, Non-metal, or Metalloid? Colour or write in the metals, non-metals, and metalloids. Be sure to classify every element into 1 of the 3 categories.
Metals, Non-metals, and metalloids Now that you know where they are located on the periodic table, you need to describe the properties of metals, non-metals, and metalloids. Fill in the next three slides by using your own prior knowledge and new knowledge you gained from your textbook.
Important Families of the Periodic Table The important groups (for the purposes of Science 9) on the periodic table are groups 1, 2, 17, and 18. They are: Alkali Metals, Alkaline Earth Metals, Halogens, and Noble Gases. Be able to locate groups on the periodic table and describe some of their properties.
Noble Gases Noble Gases are group 18 of the periodic table (very right- hand-side) They are non-metals (they are to the right of the staircase) They are very non-reactive (don’t form compounds or ions) because their valence shells are already full Noble gases are the most stable (least reactive) of all elements because of the their full valence shells
Noble Gases, Cont’d. lowest melting points of all elements (e. g. negative 272 °C for helium) Often used in lighting (they glow different colours when electricity is passed through them); “neon” lights don’t always have neon gas in them
Halogens Halogens are group 17 on the periodic table Halogens are non-metals because they are to the right of the staircase Halogens are highly reactive (form new compounds easily) because they only need one more electron to fill their valence shell. It’s pretty easy to find just one electron. Charge of 1- when they ionize (gain one electron to get a full valence shell) All halogen atoms have 7 valence electrons
Halogens, cont’d. Unlike alkaline and alkali earth metals, as you move down the periodic table, the halogens get less reactive (halogens get more reactive as you move up the periodic table) All halogens are non-metals, but iodine is a solid, bromine is a liquid, and the rest are gases They are all diatomic (eg. Cl 2 and F 2 ) They are highly reactive because they only need one electron to form a full valence shell They especially are inclined to form compounds with alkali metals (eg. NaCl) and alkaline earth metals (e. g. CaBr 2 ) Used in halogen lamps (obviously) along with the noble gases
Alkali Metals Group 1 –The most reactive metals –Get more reactive the closer they get to the bottom of the periodic table; react vigorously with water and acids. –All other metals are less reactive than alkali metals –Have an ion charge of 1+ because need to lose only one electron to have a full valence shell (one electron in the outer shell) –Called “alkali” metals because they form bases (a. k. a. “alkaline compounds”), such as NaOH and KOH –When metals do react with acids, H 2 gas is usually released. 2HCl + K KCl + H 2 See pages 238 - 239
Akali Metals, cont’d. Very reactive because it’s easy to remove that one loosely-bound electron Often form salts with halogens (e. g. LiF), donating their one valence electron to fill the one empty valence spot that the halogen has
Alkaline Earth Metals Group 2 More reactive than other metals (but less reactive than the alkali metals) Reactivity increases moving down the periodic table Form salts with halogens (e.g. CaCl 2 ) Have an ion charge of 2+ because lose 2 electrons to have a full valence shell
Alkaline Earth Metals, cont’d. Easily lose their 2 valence electrons to form ions (quite reactive but not as reactive as alkali metals) Also form alkaline solutions (bases), such as Mg(OH) 2 and Ca(OH) 2 Called alkaline EARTH metals because they are found in the EARTH’S crust Used in fireworks because they give off different coloured flames
In Summary Each group of elements share similar characteristics to other elements within their same groups These shared properties are due solely to the fact that all members of one group share the same number of valence electrons Conclusion: the number of valence electrons in an element determines the properties of that element