Periodic table and Bonding
- Created by: ajcoolatboo1
- Created on: 22-03-15 14:40
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- Periodic Table
- The periodic table lists all the known elements
- It has horizontal rows called periods and vertical columns called groups
- The group number tells you how many outer electrons the atom has
- The number of outer electrons in the atom determines how an element reacts
- The periodic table lists the elements in order of atomic number
- Noble gases are unreactive because they have full outer shells
- Eight in a shell
- Atoms with fewer than eight outer electrons react in ways that give them a stable group of eight in their outer shell.
- In a water molecule, an oxygen atom needs 2 more electrons to have eight in its outer shell
- A hydrogen atom needs one more electron to become stable
- Oxygen forms 2 covalent bonds, one with each of 2 hydrogen atoms. This way all the atoms achieve a noble gas configuration
- To form an ionic bond in sodium chloride the chloride atom gains an electron to get an outer shell of eight
- It is now a negatively charged chloride ion. The electron comes from the sodium atom. This has 8 electrons, so it is stable.
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