https://padlet.com/GemmaGreenow/3sxg03pe171r c h e m i s t r y en-us 2016-12-03 11:35:11 UTC 2025-11-01 00:10:13 UTC hello@padlet.com GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541026 a bond formed by the electrical attraction between positive and negative ions]]> 2016-12-03 11:36:57 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541026 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541042 has a pair of shared electrons with opposed spin shared between two atoms with each atom giving one electron]]> 2016-12-03 11:37:37 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541042 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541089 a covalent bond in which both electrons come from one of the atoms]]> 2016-12-03 11:38:58 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541089 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541115 2016-12-03 11:39:35 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141541115 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141556571 In a covalent bond, electron pair isn't usually shared evenly between the two unless they are the same resulting in one atoms being slightly negative charge and the other becoming slightly positive and the bond is now said to be polar. Coordinate bonds are always polar; as the atom giving both electrons can't completely lose its rights over one electron.
Pauling electronegativity values: Some EN values: H: 2.1, C: 2.5, N: 3.0, O: 3.5, F: 4.0. If the EN difference equals 0, bond is said to be pure covalent, if its between 0 and 2.1, bond is polar covalent and if it is greater than 2.1, it is pure ionic.]]> 2016-12-03 17:25:05 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141556571 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141559261 is a measure of the electron-attracting power of an atom in a covalent bond]]> 2016-12-03 18:23:30 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141559261 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141559356 Between molecules: intermolecular & within molecules: intramolecular. Intermolecular bonding is weak and governs properties like boiling temperature. Intramolecular bonding is strong and governs the molecules chemistry. Intermolecular bonding is caused by the electrical attraction between opposite charges & if the electronegativities are no the same, the molecule will have a dipole. If these dipoles arrange themselves so that the negative region of one atom is close to the positive region of another molecule there will be a net attraction between them. Even molecules without a dipole show intermolecular bonding: electrons are in constant motion and influence neighbouring molecules and induce the opposite charge forming an attraction. Therefore there are two types of intermolecular bonding: dipole and induced-dipole- Van der Waals' forces. ]]> 2016-12-03 18:25:30 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141559356 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141559816

Van der Waals' forces: 3kJ

Hydrogen bonds: 30kJ

Intramolecular bonds: 300k

]]> 2016-12-03 18:36:53 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141559816 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560116 Only occurs between molecules that contain hydrogen atoms bonded to highly electronegative elements having lone pairs: fluorine, oxygen&nitrogen. Stronger than Van der Waals' forces.]]> 2016-12-03 18:42:50 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560116 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560395 Hydrogen atom is partially positive being attached to electronegative oxygen; other molecules are closely attracted to it. Bonding is strongest when 3 atoms are is a straight line, however as oxygen has 2 lone pairs, tetrahedral structure is formed.]]> 2016-12-03 18:46:31 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560395 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560692 Same as covalent bond but both electrons come from one of the atoms- shown by an arrow. e.g. NH4+]]> 2016-12-03 18:51:51 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560692 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560721 boiling temperatures increase with strength of intermolecular forces. Van der Waals' forces cause a steady increase in BP; dipoles become larger. Hydrogen bonds cause a complete change in BP as the bonds must be largely broken .
Solubility in water
As well as hydrogen bonding with other water molecules, they can dissolve other molecules i.e. lower alcohols as they can hydrogen bond. Non-polar molecules can't hydrogen bond and are insoluble and prefer to interact with one another through Van der Waals' forces.]]> 2016-12-03 18:52:14 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141560721 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141561052 Shapes of covalent molecules with more than two atoms and their ions are governed by the electron pairs around the central atom. These may be bonding pairs or lone pairs. 2 points to look out for: how many electron pairs are connected to other atom and how many electrons are there in total? Due to all electron pairs repelling one another, the molecule shape taken up allows pairs to take up positions as far apart as possible to minimise repulsion energy. While bonding pairs are spread out between two atoms, lone pairs stay close to central atom and repel more, giving repulsion sequence:
lone pair-lone pair > lone pair-bond pair > bond pair-bond pair]]> 2016-12-03 19:00:27 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141561052 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141561500 Valence shell electron pair repulsion
Lets us predict the shapes of a molecules in which bonded atoms are arranged around a central atom. Valence shell is where bonding occurs. No. of electron pairs is first found to give general shape.

Exact angles between bonds will change based on repulsion sequence, i.e. in H2O, two lone pair and lone pair-bond pair repel the normal tetrahedral shape with angle of 109 degrees dow to 104 degrees.]]> 2016-12-03 19:13:11 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141561500 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141561634 No. Pairs - shape - bond angle - example
2 - linear -180 degrees - CO2
3 - trigonal planar - 120 degrees - BF3
4 - tetrahedral - 109.5 degrees - CH4
5 - trigonal bipyramid - 90/120 degrees - PCl5
6 - octahedral - 90 degrees - SF6]]> 2016-12-03 19:17:04 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141561634 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605578 is the weak bonding holding the molecules together, e.g. as in liquids and governs the physical properties of the substances.]]> 2016-12-04 16:50:38 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605578 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605585 2016-12-04 16:50:44 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605585 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605598 Each atom gives one electron for form a bond pair in which the electron spins are opposed.]]> 2016-12-04 16:50:54 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605598 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605621 One atom gives one or more electrons to the other resulting in a cation and anion, attracting one another electrically. Ions form a lattice in which each cation is surrounded by several anions & vice versa.]]> 2016-12-04 16:51:10 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605621 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605623 the hydrogen bond is a relatively strong intermolecular bond having a hydrogen atom joined to a highly electronegative element in a molecule and bonded to another electronegative element in another molecule]]> 2016-12-04 16:51:15 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/141605623 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144102401 Lattice of positive ions held together by a sea of delocalised electrons given up by each atom.]]> 2016-12-16 17:32:18 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144102401 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144103896 is the strong bonding between the atoms in the molecule and governs its chemistry]]> 2016-12-16 17:38:22 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144103896 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144104157 include all types of intermolecular force whether dipole or induced dipole]]> 2016-12-16 17:39:32 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144104157 GemmaGreenow https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144104363 Bonding results from electrical attractions&repulsions between protons&electrons, w/ attractions outweighing the repulsions. In covalent bonds the electrons in the pair between atoms repel one another but this is overcome by their attractions to BOTH nuclei. If atoms get too close together the nuclei and their inner electron will repel those of the other atom so that the bond has a certain length. Electron spins must be opposite for bond to form. In an ionic bond, cations&anions are arranged so that each cation is surrounded by several anions and vice verse to maximise attraction and minimise repulsion. Repulsions from inner electrons and nuclei prevent the ions from getting too close together.]]> 2016-12-16 17:40:35 UTC https://padlet.com/GemmaGreenow/3sxg03pe171r/wish/144104363