Flashcards
1_chemistry AS level topic 2 bonding
Cards in this deck (32)
- 1definition of ionic bondingstrong electrostatic force of attraction between charged molecules, due to transfer of electrons
- 2how does ionic radius have an affect on bond strengthsmaller ones can pack closer together so will have a stronger attraction
- 3how does ionic charge have an affect on bond strengthgreater charge means stronger bonds, so higher melting and boiling points too
- 4what are ionic radii trends down a group, and whythey get bigger, since there is a higher atomic number and there are more electron shells
- 5how do physical properties provide evidence for ionic bonding-high melting points due to strong attraction
-soluble in water but not in non polar substances, since they're charged
-only conduct electricity when molten or liquid
-they're brittle and cant be shaped - 6how does migration of ions provide evidence for ionic bondingelectrolysing ionic compounds give different colours at the anode and cathode, showing that one is negative and the other positive (they are charged)
- 7what is a cathode/anodecathode = negative stick
anode = positive stick - 8definition of a covalent bondstrong electrostatic force of attraction between two nuclei and the shared pair of electrons between them
- 9what is a dative bonda covalent bond where both electrons come from one atom
- 10what is bond lengthdistance between the two nuclei in a covalent compound. this is where the attractive (toward the electrons) and repulsive (from each other) forces balance out
- 11how does electron density affect bond length and enthalpymore shared electrons, stronger force, smaller length and higher bond enthalpy
- 12what is molecular shape determined byrepulsion between the electron pairs surrounding the central atom
- 13what are the different names for each shape of a molecule2 ELECTRON PAIRS
linear
3 ELECTRON PAIRS
trigonal planar
bent
4 ELECTRON PAIRS
tetrahedral
trigonal pyramidal
bent
5 ELECTRON PAIRS
trigonal bipyramidal
seesaw
distorted T
6 ELECTRON PAIRS
octahedral
square pyramidal
square planar - 14what is electronegativityability of an atom to attract to the bonding electrons in a covalent bond
- 15what is polaritya difference in electronegativity
- 16how to tell if something is more electronegativeincreases with higher charge and smaller radius.
therefore increases across period and up a group
(or look at Pauling scale!!!) - 17what are the three types of IM forcesLondon
dipole - dipole
hydrogen - 18describe London forces-occur in everything
-can hold molecules in a lattice
-stronger London forces when there are larger electron clouds, and larger surface area - 19describe dipole - dipole forces-stronger than London forces
-occur in polar molecules - 20describe hydrogen bonding-strongest of them all
-occurs between hydrogen and oxygen, nitrogen or fluorine
-has high melting/boiling points - 21why does water have a high melting/boiling pointit can form hydrogen bonds, which are very strong and take a lot of energy to overcome
- 22why does ice float/why is it less denselattice structure, so more space between the hydrogen bonds.
As it melts, some bonds are broken allowing molecules to fill the space.
This shows that it is much less dense and can therefore float on water. - 23why do alcohols have high boiling pointsthey always have a hydroxyl group, which is polar (oxygen negative hydrogen positive).
this helps oxygen to form a hydrogen bond with another positive hydrogen - 24for a substance to dissolve in another, what has to happen-bonds in the substance have to break
-bonds n the solvent have to break
-new bonds have to form between them - 25describe polar and non polar solventsPOLAR = polar molecules, but don't necessarily form hydrogen bonds
NON-POLAR = non polar molecules such as hexane (where they balance each other out) - 26why can ionic substances dissolve in waterwater is polar, and ionic substances also have charged parts. therefore the opposite charges will attract to form new bonds between the solvent and substance.
- 27why can alcohols dissolve in waterthey have a hydroxyl end which is polar, so will attract to the charged parts in H2O (H is positive, O is negative).
it is less soluble than Ionics though since the alcohol chain isn't attracted to water - 28why can halogenoalkanes dissolve in waterthey only have dipole dipole bonds so cant break the hydrogen ones in water. they will however bond with other dipole dipole bonded substances without hydrogen bonds.
- 29state the properties of ionic bondingPOINTS - high
STATE - solid
SOLID CONDUCTS - no
LIQUID CONDUCTS - yes
SOLUBLE - yes - 30state the properties of simple covalent bondinglow
usually gas/liquid (but iodine is solid)
no
no
depends on hydrogen bonds - 31state the properties of giant covalent bondinghigh
solid
no
no
no - 32state the properties of metallic bondinghigh
solid
yes
yes
no
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- chemistry as level topic 1
- Created by
- Talya Hambling · Dec 2015
- Updated
- May 28, 2016
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- Created by Talya Hambling · Dec 24, 2015
- Copied by Talya Hambling · Dec 24, 2015
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