The electrostatic force of attraction between oppositely charged ions formed by electron transfer
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What do metal atmose loss?
Electrons to form +ve ions
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What do non metal atoms do?
gain electron to form -ve
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When is the ionic bonding stronger and the melting point higher?
When the ions are smaller or have higher charges
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Why does MgO have a higher melting point that NaCL?
Mg2+ & O2- are smaller and have higher charges than those in NaCL, Na+ & CL-
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What is the definition of covalent bond?
Shared pair of electrons
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When does a dative covalent bond form?
The shared pair of electrons in a covalent bond come from only one of the bonding atoms
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What is a dative covalent bond also called?
Co-ordinate bonding
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What is the definition of a metallic bond?
The electrostatic force of attraction between the positive metal ions and the delocalised electrons
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What are three factors that affect the strength of a metallic bond?
Number of protons, number of delocalised electrons per atom, size of ion
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Why is Mg stronger metallic bonding than Na and hence a higher melting point why?
The metallic bonding gets stronger because in Mg there are more electrons in the outer shell that are released to the sea of electrons
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Why else?
The Mg ion is also smaller and has one more proton
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What is a simple molecular covalent?
Intermolecular forces(van de waals, permanent dipoles, hydrogen bonds between molecules
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What are some examples of this?
Iodine, Ice, CO2, water and methane
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Why is a boiling and melting points high on ionic bonding?
Giant lattice of ions with strong electrostatic forces between oppositely charge ions
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Why can't they conduct electricity when solid?
the ions can't move fixed in lattice
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Why do the macromolecules have high melting and boiling points?
many strong covalent bonds in macrocolecular structure, take a lot of energy to break the many strong bonds
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Why is graphite a good conductor?
free delocalised electrons between layers
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What is the definition of electronegativity?
An atom's ability in a covalent bond to attract electrons in a covalent bond to itself in a molecule
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Why does Electronegativity increase across a period?
The number of protons increases and the atomic radius decreaes because the electrons in the same shell are pulled in more
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Why does Electronegativity decrease down a group?
The distance between the nuceleus and the outer electrons increases and the shielding of inner shell electrons increases
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When does a polar covalent bond form?
When the elements in the bond have different electronegativies
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Where do Van der waal forces occur?
Between all molecular substances and noble gases
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Where do they not occur?
between ionic substances
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What is the main factor affecting size of van der waal forces?
The more electrons there are in the molecule the higher the chance that temporty dipoles will form. This makes the Van der waals stronger bettween the molecules and so bp will be greater
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How can the increasing boiling points of the halogens down the group 7 series be explained?
The increasing number of electrons in the bigger molecules causing an increase in the size of van der waals between the molecules
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When does permanent dipole dipole bonding occur?
Between polar molecues
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When does hydrogen bonding occur?
It occurs in compounds that have a hydrogen atom attached to one of the three most electronegative atomos of nitrogen, oxygen and fluorine which must have an available lone pair
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Why do diamonds and graphite have high boiling and melting points?
Strong covalent forces in the giant structure, it takes a lot of energy to break the many strong covalent bonds
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Other cards in this set
Card 2
Front
What do metal atmose loss?
Back
Electrons to form +ve ions
Card 3
Front
What do non metal atoms do?
Back
Card 4
Front
When is the ionic bonding stronger and the melting point higher?
Back
Card 5
Front
Why does MgO have a higher melting point that NaCL?
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