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23 Cards in this Set
- Front
- Back
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What is a covalent bond? |
A covalent bond is where atoms achieve a stable electron arrangement by sharing electrons. As a result the outer energy level is filled, therefore making them stable. |
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What are the two types of structure that a covalent substance can form?
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Molecule and network |
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How are atoms held together in a covalent bond? |
Atoms in a Covalent bond are held together by the equal attraction between the two positive nuclei and the shared pair of electrons |
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What are the 4 types of shapes for covalent molecules? |
Linear, Bent, Pyramidal, Tetrahedral |
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What is the only element to form a covalent network? |
Silicon (Si) |
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Why does a covalent network have very high melting and boiling points? |
The bonds holding the atoms together are very strong, which means a lot of energy is required to break them. |
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Why do covalent molecular substances have low boiling and melting points? |
The bonds that hold the atoms together are very weak, which do not require a lot of energy to be broken |
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Why don't covalent substances conduct? |
Because they have no free moving ions or electrons. |
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How are ionic compounds held together? |
Ionic lattices are held together by the attraction between the positive and negative ions. |
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Why do ionic compounds conduct when molten or dissolved in a solution, but not as a solid? |
They cannot conduct as a solid because the ions are not free to move. When molten, the lattice broken, which allows the ions to move and conduct. |
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Why do metals conduct? |
Because they have delocalised electrons. |
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What is an insulator? |
A material or substance that does not allow electricity to pass through. |
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What is electrolysis |
Electrolysis is the process by which electricity is passed through a ionic compound to break it down into its elements |
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During electrolysis, which type of power pack is used, and why? |
DC, to identify the products |
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What is the location, charge and mass of a proton? |
Inside nucleus, positive and 1 amu
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What is the location, charge and mass of a neutron? |
Inside nucleus, no charge and 1 amu
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What is the location, charge and mass of a neutron? |
Outside nucleus in energy levels, negative charge and 0 amu
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What are the 7 diatomic elements?
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Hydrogen, Iodine, Nitrogen, Chlorine, Bromine, oxygen and Fluorine |
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What is the atomic number equal to?
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Number of protons |
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What is the mass number equal to? |
Number of protons plus number of neutrons |
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What are ions?
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An atom that has lost or gained electrons |
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When metals become ions, what happens to their number of electrons?
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They lose electrons, making them positive |
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What are isotopes?
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Isotopes are different forms of the same atom. They have the same atomic number but different mass number. Therefore they gain neutrons |
