19290463
Description
Flashcards by Daniella Belonohy, updated more than 1 year ago
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Created by Daniella Belonohy
over 4 years ago
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| Question | Answer |
| Describe a covalent bond, example, and its electronegativity values | Two atoms share one or more pairs of electrons, F2, electronegativity difference is small or 0 |
| Describe a polar covalent bond, example, and its electronegativity values | An asymmetric distribution of electrons, HF, electronegativity difference is intermediate between 0.5 and 1.7 |
| Describe an ionic bond, example, and its electronegativity values | Electrostatic attraction between oppositely charged ions, formed between very different electronegativities. LiF, A large EN between 1.7 and 3.3 |
| What is electronegativity, and how does it appear on a periodic table? What happens to the atomic radius, valence electrons and their power as the electronegativity increases (across) | The tendency of an atom in a molecule to attract electrons towards itself, increases up and to the right, the most electronegative atom being Fluorine. Atomic radius decreases, valence electrons are closer to nucleus, and greater power on valence shell electrons |
| Difference between anions and cations | Anions: add electrons Cations: subtract electrons |
| Lewis structure method: | Determine valence electrons Place least electronegative in centre of atom (remember that O,F, Cl are usually terminal (outside)). Place non-bonding electrons on outer edge Assign remaining valence electrons Minimise formal charges on atoms |
| Formal charge formula | F.C= #valence e in neutral atom - #total e in lone pairs - (e in covalent bonds/2) |
| Octet rule | First two rows tend to obey octet rule as the 2s and 2p orbitals can only accomodate 8 e-. Third row will satisfy rule but can exceed if there are vacant d orbitals. |
| What does the 'n' quantum symbol mean? | The principal Quantum Number Describes size and energy levels Positive integer values |
| What does the 'q' quantum symbol mean? | The angular momentum Describes shape of the orbital that the electron occupies s=0, p=1, d=2, f=3 0 to n-1 |
| What does the 'ml' quantum symbol mean? | The magnetic quantum number Describes orientation in space of orbital (given n and l). 2l+1 orbitals in each subshell ...-2,-1,0,1,2... |
| What does the 'ms' quantum symbol mean? | The spin quantum number Describes orientation of the spin axis +1/2 or -1/2 |
| Difference between diamagnetic and paramagnetic | Diamagnetic means all the electrons are paired. These are not attracted to magnets. Paramagnetic means there are unpaired electrons. These are weakly attached to magnets. |
| What is the Pauli exclusion principle? | No two electrons in the same atom can have identical values for all four of their quantum numbers. |
| What is the Aufbau principle? | Also known as "building-up". It is the increase of energy of the subshells. |
| What is Hund's rule? | When electrons are placed in orbitals of equal energy, they spread out as much as possible to give as few paired electrons as possible. |
| What is VSEPR theory and what are the degrees of repulsion? | The (VALENCE SHELL ELECTRON PAIR REPULSION THEORY) is used to predict geometry of molecules from number of electron pairs surrounding central atom. It is based on minimising the electrostatic repulsion of a molecules valence e around central atom Lonepair/lonepair > bondingpair/lonepair> bondingpair/bondingpair |
| Geometry of (no lone pairs) sp hybridised sp2 hybridised sp3 hybridised sp3d h sp3d2 | sp = linear geometry - 180' bond angle sp2= trigonal planar - 120' bond angle sp3 = tetrahedral - 109.5' bond angle sp3d = trigonal bipryamidal - 90 and 120' bond angles sp3d2 = octahedral - 90' bond angles |
| Geometry of sp3 hybridised (1 lone pair) sp3 hybridised (2 lp) | sp3 hybridised = tetrahedral geometry, so is trigonal pyramidal molec geometry tetrahedral, but bent |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 2 electron pairs, no lone pairs | Linear, Linear, 180' |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 3 electron pairs, no lone pairs | Trigonal planar, trigonal planar, 120' |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 3 electron pairs, 1 lone pairs | Trigonal planar, bent, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 4 electron pairs, no lone pairs | Tetrahedral, tetrahedral, 109.5' |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 4 electron pairs, 1 lone pairs | Tetrahedal, trigonal pyramidal, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 4 electron pairs, 2 lone pairs | Tetrahedral, bent, 104.5' |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 5 electron pairs, no lone pairs | Trigonal bipyramidal, trigonal bipyramidal, 90' and 120' |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 5 electron pairs, 1 lone pairs | Trigonal bipyramidal, seesaw, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 5 electron pairs, 2 lone pairs | Trigonal bipyramidal, T shaped, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 5 electron pairs, 3 lone pairs | Trigonal bipyramidal, linear, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 6 electron pairs, no lone pairs | Octahedral, octahedral, 90' |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 6 electron pairs, 1 lone pairs | Octahedral, square pyramidal, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 6 electron pairs, 2 lone pairs | Octahedral, square planar, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 6 electron pairs, 3 lone pairs | Octahedral, T-shaped, * |
| What is the electron-pair geometry, molecular geometry and bond angle of: A molecule with 6 electron pairs, 4 lone pairs | Octahedral, linear, * |
| What are the five main electron pair geometry names from 2-6 | Linear, trigonal planar, tetrahedral, trigonal bipyramidal, octahedral |
| What are axial and equatorial sites | They are in trigonal bipyramidal electron pair geometry. Axial = Has three 90' interactions (theyre on top & bot) Equatorial = Has two 90' and two 120' interactions, lone pairs occupy these sites |
| Describe the overlapping and strength of sigma and pie bonds | Sigma=Physical overlap, strongest bond Pi=Lateral overlap, relatively weak bonds |
| Understand the hybridisation of this picture | ok |
| Polar vs non-polar molecules | Polar = Bond dipoles do not cancel out Non-polar= bond dipoles cancel out |
| What is the shape, bond angle and types of bonds in: sp sp2 sp3 | sp = linear, 180', 2 sigma + 2 pi sp2 = trigonal planar, 120', 3 sigma, 1 pi sp3 = tetrahedral, 109.5', 4 sigma |
| What are dipole moments? | Dipoles refer to the net electrical character from an asymmetric charge distribution. They depend on bond polarities (stronger polarity = larger dipole) and its molecular shape (symmetrical molecules cancel out bond polarities) |
| What determines bond length? | The more electrons in the bond between them, the shorter the bond (i,e, triple shorter than double etc) The larger the electronegativity difference between the bonded atoms, the shorter the bond The larger the bond order = stronger The shorter it is = the more stable |
| What is the bond order equation? | (Bonding electrons - antibonding electrons)/2 |
| Describe how wave functions can interact in orbitals | Wave functions can interfere constructively (waveA+WaveB) or destructively (waveA-waveB) Destructive interference = antibonding/out of phase Constructive interference = bonding orbital/in phase |
| What is bond energy? | The amount of energy required to break a chemical bond. More electrons = increase energy Longer = decrease energy Increasing electronegativity difference = increase energy |
| Rules for hybridisation | Hybridise central atom only Only use valence electrons Number of hybrids = number of atomic orbitals used Any electrons remaining go into unhybridised orbitals (form pi bonds) |
| What are isomers | Same molecular formula, atoms arranged different ways. They are different compounds with different properties |
| In uncharged molecules, state the valences for each atom: C, O, F, Br, H, N, Cl, I | C=4, O=2, F=1, Br=1,H=1,N=3,Cl=1,I=1 |
| What is this group? Suffix? | Carboxylic Acid -oic acid |
| What is this group? Suffix? | Ether -ane |
| What is this group? Suffix? | Alcohol/Hydroxyl -ol |
| What is this group? Suffix? | Ester -oate |
| What is this group? Suffix? | Amide -amide |
| What is this group? Suffix? | Ketone -one |
| What is this group? Suffix? | Aldehyde -al |
| What is this group? Suffix? | Amine -amine |
| What can J*sec also be as a unit? | m^2*kg*s-1 |
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