C3.1 The Periodic Table
- Created by: lilyb1509
- Created on: 07-04-15 18:45
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- C3.1 The Periodic Table
- 1863 -Newlands Law of Octaves
- Similar properties repeated every eighth element
- 62 elements known into seven groups according to atomic weight
- Properties did not match well within groups
- Scientists did not accept his ideas
- 1869 - Mendeleev's Periodic Table
- Gaps left for undiscovered elements
- Groups of known elements had similar properties
- Predicted properties of missing elements
- Confirmed predictions meant scientists readily accepted his ideas
- His table the basis for modern periodic table
- Confirmed predictions meant scientists readily accepted his ideas
- Modern Periodic Table
- The atomic number determines position in the periodic table
- Number of electrons in outer shell determines chemical properties
- Group number = number of electrons in outer shell
- Going down a group, there are more occupied energy levels = larger atoms
- Electrons in outer shell are less strongly attracted by nucleus
- Group One Metals
- Alkali metals
- React readily with air and water
- Reacting with water produces hydrogen gas + metal hydroxide
- sodium + water > sodium hydroxide + hydrogen
- Reacting with water produces hydrogen gas + metal hydroxide
- They lose their outer electron in reactions to form ionic compounds with a +1 charge
- Reactivity increases going down the group
- Between Groups 2 and 3
- Transition elements / metals (all metals)
- Higher melting and boiling points than alkali metals
- Stronger, harder (good for building materials) and good conductors of heat and electricity
- React slowly, or not at all, with oxygen and water
- Form positive ions with various charges
- Important industrial catalysts
- Group 7
- The Halogens
- Non-metallic
- Low melting and boiling points increase going down group
- Reactivity decreases going down group
- They form ions with a single negative charge
- The Halogens
- 1863 -Newlands Law of Octaves
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