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Description
Flashcards by megan.parlow, updated more than 1 year ago
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Created by megan.parlow
over 9 years ago
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| Question | Answer |
| Compound | Contains two or more elements that are chemically combined |
| Ionic bonding | Electrostatic attraction which forms a chemical bond between two ions |
| Covalent bond | A chemical bond that shares pairs of electrons between atoms |
| How can you tell if it is ionically or covalently bonded? | Ionic bonds involve at least one metal. Covalent bonds occur between two none metals. |
| How are compounds formed? | Elements react together to create compounds by either losing, gaining or sharing electrons. |
| Ionic Bonding | |
| Covalent bonding | |
| Losing electrons forms positive ions (because there are now more protons) | Gaining electrons forms negative ions (because there are now more electrons) |
| The formula of an ionic compound shows the ratio of ions present | Examples: Calcium Oxide - CaO Lithium Oxide - Li2O Magnesium Chloride - MgCl2 |
| Remember..... | Charges in ionic compounds always cancel each other out. The compound as a whole is nuetral. |
| Many substances containing covalent bonds are simple molecules but they can make giant covalent structures too. | When non-metal elements react together they make covalent bonds. The atoms in these bonds are held together by shared electrons. Most substances held together by covalent bonds consist of molecules, but some have giant covalent structures, sometimes called macromolecules. |
| The atoms in metals are formed in a regular pattern, layer upon layer. | This means that they form crystals. |
| Metallic bonding (an example of a giant structure) | In metallic bonding the metal ions are held together by the electons on the outermost shell of the atoms. The positive ions this produces are held together by electrostatic forces. The electrons in metals are free (delocalised) to move about the structure. |
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