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FAMILIES AND PERIODS

FAMILIES AND PERIODS. The Periodic Table. Mendeleev. Protons hadn’t been discovered in my time, so I didn’t know about atomic number. I arranged the elements by atomic mass. I’m Henry Mosley, and changed that in 1913, and reordered the table according to atomic number.

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FAMILIES AND PERIODS

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  1. FAMILIES AND PERIODS The Periodic Table

  2. Mendeleev Protons hadn’t been discovered in my time, so I didn’t know about atomic number. I arranged the elements by atomic mass. I’m Henry Mosley, and changed that in 1913, and reordered the table according to atomic number.

  3. Vertical columns are called GROUPS Mendeleev Periodic table The periodic table arranges all the elements in groups according to their properties. There are 18 groups Groups are also called Families

  4. These elements have 8 electrons in their outer shell All group 1 metals have 1 electron in their outer shell These elements have 3 electrons in their outer shells The Periodic Table Elements in the same grouphave the same number of electrons in the outer shell. These are called valence electrons.

  5. Consider the group 1 metals. They all: • Are soft • Can be easily cut with a knife • React with water The Periodic Table Since they have the same number of valence electrons, all of the elements in the same group have similar PROPERTIES. This is how I thought of the periodic table in the first place.

  6. Mendeleev Periodic table The periodic table also arranges the elements in rows, or periodsaccording to the number of energy levels. There are 7 periods Horizontal rows are called PERIODS

  7. Mendeleev The first element in a period is usually an active solid, and the last element in a period is always an inactive gas. Elements in a period are NOT alike in properties.

  8. These elements are metals This line divides metals from non-metals These elements are non-metals The Periodic Table Most of the elements are metals:

  9. Physical properties of metals • Atoms packed together closely. • Layers of atoms can slide over one another • Malleable (bendable) • Ductile (stretchable) • Conduct heat and electricity • Usually have high melting and boiling points • Exceptions: Mercury and Group I metals.

  10. Physical properties of metals • They have metallic lustre (they’re shiny) • They are sonorous (make a ringing sound when hit) • All except mercury are solids at room temperature • Only a few metals are magnetic. • Magnetism is not a property of most metals!

  11. ALKALI METALS • very reactive metals that do not occur freely in nature • softer than most other metals • can explode if they are exposed to water

  12. Group 1: Alkali Metals http://www.youtube.com/watch?v=uixxJtJPVXk Li Na K Rb Cs

  13. ALKLINE EARTH METALS • very reactive • not found free in nature

  14. TRANSITION METALS • ductile and malleable, and conduct electricity and heat • iron, cobalt, and nickel, are the only elements known to produce a magnetic field.

  15. OTHER METALS • are ductile and malleable • are solid, have a relatively high density, and are opaque

  16. NON-METALS • not able to conduct electricity or heat very well • very brittle, cannot be rolled into wires or pounded into sheets • usually exist as gases, sometimes as solids (such as carbon), and bromine is a liquid • have no metallic luster, and do not reflect light.

  17. HALOGENS • "halogen" means "salt-former" and compounds containing halogens are called "salts" • exist in three states of matter: • Solid- Iodine, Astatine • Liquid- Bromine • Gas- Fluorine, Chlorine

  18. HALOGENS • The halogens are non- metals • They all have seven electrons in their outer shell this makes them very reactive since they only have to gain one more electron to fill their outer shell. • Unlike Group One the elements get less reactive as you go down the group

  19. Group 17: The Halogens • http://www.youtube.com/watch?v=u2ogMUDBaf4 F Cl Br I

  20. NOBLE GASES • do not form compounds easily • have filled outer energy levels

  21. Group 18: The Noble Gases • http://www.youtube.com/watch?v=QLrofyj6a2s He Ne Ar Kr Xe

  22. Metalloids • Metalloids are a group of elements that exhibit • Properties of both metals and non-metals. • Stair-step pattern divides metals(left) and non-metals(right)

  23. RARE EARTH ELEMENTS • many are man-made

  24. RARE EARTH ELEMENTS • Broken into two groups. • Lanthanides • Actanides

  25. RARE EARTH ELEMENTS • Lanthanides- Top row. • non-radioactive metals • used in making glass

  26. RARE EARTH ELEMENTS • Actanides – Bottom row • Radioactive • Expensive - $$$ • Found only in trace amounts

  27. Your Task Today! • Create a Key on your periodic table to help you understand the different groups. • Create a colored box and provide a title for that group. • Write a brief description of the group • Ie: a Dark blue box = Alkali Metals – Very reactive, one valence electron, become more reactive as we go down the family, soft metals, react with water.

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