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48 Cards in this Set
- Front
- Back
Good conductor, Soft, very high melting point -Describe the bonding and structure in Graphite -Explain, in terms of bonding and structure, the properties of graphites shown above |
Main: giant covalent lattice in layers -Good conductor - because it has mobile electrons ORde-localised electrons. -High melting point - because strong covalentbonds have to be broken Soft- weak intermolecular forces between the layers |
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Explain what is meant by a covalent bond. |
a shared pair of electrons |
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Dot and cross- NH3 |
- |
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Name the shape of the ammonia molecule and explanation. |
Name: Pyramidal or (trigonal) pyramid Explanation: -There are 3 bonded pairs and 1 lone pair -Lone pairs repel more than bonded pairs |
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Complete the electron configuration of the cl(-) ion. |
1s2 2s2 2p6 3s2 3p6 |
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Dot and Cross of NH4+ |
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State the shape of, and bond angle in, an NH4= ion. |
Shape: tetrahedral Bond Angle: 109.5Oc |
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Ammonium chloride solid don't conducts however dissolved in water it conducts Explain why. |
-ions cannot move in a solid -ions are mobile in solution |
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Explain, with diagram, what is meant by the term metallic bonding. |
-metallic bond as (electrostatic) attraction between theelectrons and the positive ions |
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State what is meant by the term ionic bond |
(electrostatic) attraction between oppositely charged ions |
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Compare and explain the electrical conductivities of sodium and sodium oxide in the solid andliquid states |
- sodium is a (good) conductor because it has mobile delocalised electrons
-sodium oxide does not conduct as a solid ions cannot move in a solid -sodium oxide conducts when it is a liquid ions are mobile when liquid |
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State what is meant by the term atomic number. |
number of protons (in the nucleus) |
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Complete the full electron configuration for a titanium atom. |
(1s2) 2s2 2p6 3s2 3p6 3d2 4s2 |
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Explain, with the aid of a diagram, the intermolecular forces in H2O that lead to the relatively high boiling point of H2O. |
relatively strong hydrogen bonds between O and H. |
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Suggest why H2S has a much lower boiling point than H2O. |
-no hydrogen bonding -weaker intermolecular forces |
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What is meant by the term ionic bonding? |
-(Electrostatic) attraction between oppositely chargedions. |
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Draw a "dot-and-cross" diagram of a molecule of f20 |
Draw: |
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Predict the bond angle in an f20 molecule. Explain your answer. |
Predicted bond angle 104–105Oc. There are 2 bonded pairs and 2 lone pairs Lone pairs repel more than bonded pairs |
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Describe and explin one anomalous property of water which results from hydrogen bonding |
-Liquid H2O is denser than solid -In solid state H2O molecules are held apart byhydrogen bonds OR ice has an open lattice -H2O has a relatively high boiling point OR meltingpoint -hydrogen bonds are relatively strong |
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Describe the structure and bonding shown by these elements. |
-Mg has a giant structure -Mg has metallic bonding OR description of metallic bonding as positive ions and delocalised electrons -(There is electrostatic attraction between) positiveions and electrons -Cl has a simple molecular OR simple covalent(lattice) -temporary dipole–temporary dipole |
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Describe, with the aid of a labelled diagram, the structure and bonding in lithium and explain why lithium has a high boiling point. |
-The attraction between + ions and e– is strong OR metallic bonding is strong |
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Explain why fluorine has a low boiling point |
- F2 has induced dipoles -London dispersion force - which are weak |
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Explain why lithium fluoride conducts electricity when molten but not when solid. |
-Ions cannot move in a solid -Ions are mobile when molten |
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Name the shape of, and state the bond angles in, a BF3 molecules. Explain why BF3 has this shape. |
Shape: trigonal planar Bond angle: 120° Explanation:Pairs of electrons repel (one another equally) Boron has 3 bonded pairs (and 0 lone pairs) |
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Nitrogen can also form a fluoride, NF3, which has a permanent dipole. Explain why NF3 has a permanent dipole. |
-F is more electronegative than N -Dipoles do not cancelORNF3 is pyramidal (in words) / asymmetrical |
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What is meant by the term ionic bonding? |
-(Electrostatic) attraction between oppositely chargedions |
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Explain why a solution of copper(II) nitrate conducts electricty |
Ions are mobile |
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What is meant by the term electronegativity |
The ability of an atom to attract electrons |
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State the shape of a molecule of SF6 |
Octahedral |
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Explain, in terms of inter-molecular forces present, why IcL has a higher boiling point than Cl2 |
Exp1:ICl has permanent dipole (–dipole) (interactions)
-Cl2 has (only) London dispersion -Forces are stronger in ICl and more energy is needed to overcome forces in icL Exp2:-ICl has more electrons -Stronger london dispersion forces in ICl(than in Cl2) and therefore More energy is needed to overcome london dispersion forces in ICl |
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Explain why there is a difference in the melting points of K, KBr and H20 |
-In KBr, electrostatic attraction between oppositely charged ions.KBr has ionic bonding AND -In K, electrostatic attraction between positive ions/cation.K has metallic bonding AND K has attraction between positive ions and electrons -In H2O, hydrogen bonding Between molecule Order of strength of forces: KBr > K > H2O |
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Why can ammonium sulfate be described as a salt? |
H+ ions in sulfuric acid are replaced with ammonia ions. |
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state what is meant by the term covalent bond |
A shared pair of electrons |
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Explain how chemists can predict shape of a simple covalent molecule from the number electron pairs surrounding the central atom. |
-Pairs of electrons surrounding a central atom repel -The shape is determined by the number of bond pairs -the number of lone pairs of electrons |
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Predict the O-B-O and B-O-H bond angles in a molecule of H3BO3. |
O-B-O=120o B-O-H= 104.5o |
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Give an example of a simple covalent molecules which has all bond angle of 90o |
SF6 OR sulfur hexafluoride |
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Chlorine is more reactive than bromine. Explain why? |
-Chlorine will gain an electron more easily than bromine -(An atom of) chlorine is smaller (than bromine) -(Outermost shell of) chlorine is less shielded (than bromine) -Nuclear attraction (on the electron to be gained) by chlorine is greater (than bromine) |
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Explain why there is a difference in the boiling points of HCl and F2? |
-F2 has temporary OR instantaneous dipole(–dipole)attraction OR interactions -HCl has permanent dipole(–dipole) attractions ORinteractions -intermolecular force in HCl is stronger than that in F2 -more energy is required to break stronger (intermolecular)forces |
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WHat are the main intermolecular forces present in NH3 and PH3 |
-hydrogen bonding -Permanent dipole(–dipole interactions) |
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Suggest why PH3 has a lower boiling point than NH3. |
the intermolecular forces are weaker in PH3 |
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A covalent bond is a shared pair of electrons. What is a dative covalent bond? |
Both electrons have been donated by one atom |
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Draw dot and cross of H3NBF3 |
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Group 2 element react with halogens. Describe and explain the trend in reactivity of Group 2 elements with chlorine as the group is descended |
-Reactivity increases (down the group) -Atomic radius increases - There is more shielding -Nuclear attraction (to electron) decreases -Increased nuclear charge is outweighed by increased shielding/distance -Ionisation energy decreases |
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To identify iodine ion in chlorine iodine. What do you add? What what would happen? |
-Dilute silver nitrate -Yellow precipitate |
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Explain the trend across Period 2. |
-greater nuclear charge - electrons experience the same shielding - Atomic radius decreases -Greater nuclear attraction (on outermost electrons |
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Solid carbon exists in two forms, diamond and graphite. Explain why it is unnecessary to refer to carbon as either diamond or graphite. |
Diamond and graphite form gaseous atoms of carbonwhen they are ionised |
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Complete table |
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-(N in) NH3 has three bonding pairs and one lone pair ofelectrons - (N in) H3NBF3 has four bonding pairs (and no lone pairs)of electronsORLone pair on N now becomes bonding pair - Lone pair of electrons repels more than bonding pairs |