Bonding

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What is ionic bonding?
strong electrostatic forces of attraction between opposite charged ions held in a lattice
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Give an example of an ionically bonded substance
NaCl
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How high are ionically bonded substances b.p & m.p?
High- takes a lot of energy to break strong electrostatic forces of attraction between oppositely charged ions
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Do ionic substances conduct electricity?
Yes, when moleten/in solution as the ions are free to move and carry charge
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What is simple molecular covalent bonding?
Strong covalent bonds between atoms, weak Van der Waals forces of attraction between molecules
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Are there any lone pairs in simple covalent bonding?
No- all involved in bonding
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Can simple molecular covalent molecules conduct electricity? Why?
No- all the electrons are used in bonding and aren't free to move
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Do simple molecular substances have a high/low m.pt/ b.pt? why?
Low- weak Van der Waals forces of attraction between molecules that don't take much energy to overcome
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Describe macromolecular covalent bonding
Lattice of many atoms held together by strong covalent bonds
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Do substances with macromolecular covalent bonds have high m.pt/b.pt?
High, as it takes a lot of energy to overcome many strong covalent bonds
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Do substances with macromolecular covalent bonds conduct electricity?
Electrons are used in bonding so most don't
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Describe structure of diamond
3D tetrahedral structure of C atoms with each C bonded to four others
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Draw and describe structure of graphite
Macromolecular covalent but each C only bonds to 3 others so it is layers. Weak Van der Waals forces of attraction between layers means they can slide over each other- malleable. One electron from each carbon is delocalised and can carry charge
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Describe metallic bonding
Lattice of positive ions surrounded by sea of delocalised electrons. Layers can slide over each other
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Do metallic compounds have high/low m.pt & b.pts? Why?
High as strong forces of attraction between positive metal ions and negatively charged sea of delocalised electrons
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Do metallic compounds conduct electricity? Why?
Yes as delocalised electrons can move throughout the metal to carry charge
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How does the strength of metallic bonds change across the periodic table? why?
increases as there are higher mp/bps and higher charge on metal ions more delocalised electrons per ion and stronger force of attraction between them
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Define electronegativity
the ability of an atom to attract the pair of electrons (electron density) in a covalent bond
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What effects electronegativity
nuclear charge, atomic radius and electron shielding
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Most electronegative element?
Flourine, largest nuclear charge for its electron shielding, small atomic radius
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How do you a non-polar bond?
both bonding elements have the same electronegativites
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When do you get a polar bond?
when bonding atoms have different electronegativities
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What is the strongest intermolecular force and what is the weakest?
Hydrogen bonding and weakest is Van der Waals forces
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Describe Van der Waals forces of attraction
Temporary dipoles are created by the random movement of electrons this induces dipole in neighbouring molecule and temporary induced dipole-dipole attraction aka Van der Waals forces of attraction
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Are Van der Waals forces stronger in smaller or larger molecules?
Larger
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Describe permanent dipole-dipole attraction
Some molecules with polar bonds have permanent dipoles forces of attraction between those dipoles and those of neighbouring molecules
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What conditions are needed for hydrogen bonding to occur?
Nitrogen, Oxygen or Flourine because they are highly electronegative and the nucleus of hydrogen is left exposed. Strong force of attraction between hydrogen nucleus and lone pair of electrons on N,O, F
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Why is ice less dense than liquid water?
In liquid water, hydrogen bonds constantly break and reform as molecules move about. In ice the hydorgen bonds hold the molecules in foxed positions and makes them slightly further apart than in liquid water
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Other cards in this set

Card 2

Front

Give an example of an ionically bonded substance

Back

NaCl

Card 3

Front

How high are ionically bonded substances b.p & m.p?

Back

Preview of the front of card 3

Card 4

Front

Do ionic substances conduct electricity?

Back

Preview of the front of card 4

Card 5

Front

What is simple molecular covalent bonding?

Back

Preview of the front of card 5
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