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22 Cards in this Set
- Front
- Back
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STATE the meaning of the term COVALENT BOND |
SHARED PAIR of electrons |
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STATE the Gas equation |
PV=nRT |
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General formula for alkanes |
CnH2n+2 |
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Define the tern ELECTRONEGATIVITY |
The ability to attract the bonding electrons in a covalent bond. |
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DEFINE the term First Ionisation energy |
Energy required to remove 1 electron from each atom in 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions. |
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The DROP between Groups 2 and 3 ? |
Alluminiums outer electron is in a 3p orbital rather than 3s. The 3p orbital has a slightly higher energy than the 3s orbital. So the elctron is on avarge futher away from the nucleus. The 3p orbital has additional shielding provided by the 3s^2 electrons. These facts are enough for the inonisation energy to drop slightly. |
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The DROP between Group 5 and 6. |
The SHIELDING IS IDENTICAL in the phosphorus and sulfur atoms, and electrons is being removed from an identical orbital. In phosphorus the electeon is being removed from a singly occupied orbital. But sulfur the electron is being removed from from and orbital containing 2 electron this causes repulsion which means its easier to remove hence theres a small drop. |
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PERCENTAGE yield |
ACTUAL YIELD/THEORETICAL YIELD ×100 |
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%ATOM economy |
Mass of desired product/total mass of reactants × 100 |
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STATE the type of crystal of (a) IODINE and (b) GRAPHITE |
a) MOLECULAR b) GIANT COVALENT/ MACROMOLECULAR |
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DESCRIBE the structure of and bonding in graphite and explain why the melting point of graphite is very high. |
Graphite has layers of carbon atoms in a hexagon shape connected by covalent bonds, each layer is bonded together by VAN DER WAALS forces hence the melting point is very high because there is many strong covalent bonds to overcome. |
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EXPLAIN why IODINE vaporises whrn heated gently. |
When iodine is heated the van der waals forces between the molecules are weak and easily broken. |
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Properties and applications of Dimond. |
Dimond does not conduct electricity. Tetrahedral shape. Insoluble. It sublimes at very high temperatures therefore has a very high melting point. Graphite has a higher melting point due to delocolised electrons. Dimond tip drill and saw due to hardness. |
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What is Relative atomic mass ? |
is the avarage mass of an atom compared to one twelfth of the mass of one atom of carbon-12 |
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What is the Relative Molecular mass? |
Is the avarage mass of a molecule compared to one twelth of the mass of one atom of carbon-12 |
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state the what an ionic bond is? |
Is the electrostatic force of attraction between oppositely charged ions formed by electron transfer. |
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State what a metallic bond is. |
Is the electrostatic force attraction positive metal ions and the delocolised electrons. |
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What is a Dative covalent bond. |
Is when the shared pair of electrons in a covalent bond comes from only one of the bonding atoms. |
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What are the factors that affect a metallic bond. |
1- The more protons the stronger the bond 2- More delocolised electrons stronger the bond 3- The smaller the ion, the stronger the bond. |
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Sodium Chloride is a |
Giant Ionic lattice held together by the electrostatic force of attraction between oppositely charged ions |
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All metals |
experience the electrostatic force of attraction between the metal positive ions and the delocolised electrons |
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why is ice less dense than water |
this is because in ice the molecules are held futher apart than in liquid this causes to have a lower density |
