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Infection and response
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Biological molecules
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1f industrialisation and the people: britain, c1783-1885
1c the tudors: england, 1485-1603
Britain & the wider world: 1745 -1901
Inter-war germany
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2n revolution and dictatorship: russia, 1917-1953
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2m wars and welfare: britain in transition, 1906-1957
2d religious conflict and the church in england, c1529-c1570
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01/02/2023
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1.3.1 Tonic bonding LONTE BONO-electrostatic force of attraction between oppositely ions in a lattice METALS charged - always love elections and become positive ions NON METALS - TONIC COMPOUNDS - always gain electrons and become negative ionl • formed between a metal and non-metal I always have an overall charge of O COMPOUND/MOLECULAR ION) - made of 2. types of atom eg. 50,₂² GIANT IONIC STRUCTURES (LATTICESTU 1.5 bonding There are no molecules PROPERTIES OF TONIC COMPOUNDS ener O cr Na - Any to @ and A MELTING & BOILING POINTY Tonic compounds have high melting and boiling points because there are lots of strong electrostatic forces of attraction which to overcome require FACTORS AFFECTING THE STRENGTH OF IONIC BONDS - Each Nat attrack MECHANICAL PROPERTIES 6 C1, and verven - The ions in lonic compounds are held together by the attraction between appositely chargodions -Tonic bonding cannot exist in isolation If the layers are disrupted, the sens with the same ion will be attraded bo the electrone CHARGE ON THE ION- - The higher the charge, the stronger the honding WRITING FRAME -ion is smaller is more highly charged This meansions can form strong in electrostatic forces of attraction with the. 1003 SIZE OF THE ION - the smaller the 1011, the stronger the bonding s charge increases, size increases 4+ions: as charge increases, size decreases. 4-ions: as 4 These forces require more energy to overcome " It has higher melting & boiling points ELECTRICAL CONDUCTIVITY -Tonic compounds will only conduct electricity when they are molten or...
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dissolved "This is because when a solid, the ions are not free to move and carry the charge through the structure, but when molten of dissolved they a are charge STAESS |_ion is, this makes ionic 20 wit repel each other, and the structure will break ·compounds brittle 0 O 7 1.3.2 NATURE OF COVALENT & PATIVE COVALENT BONOS COVALENT BOND-pair of elections shared between 2 atoms ・It is the electrostate force of attraction between the + nucles pair of election, and a shared - Covalent bonds should not be regarded as shared electron in a fixed position.. • state of constant motion, best regarded as charge clouds Electrons pain in are in a - Multiple covalent boods (eg. double) contain multiple e pour STRENGTH OF GOVALENT BONDY - All covalent bonds are considered generally strong - The smaller the atoms, the closes the elections are to the 2 nuclei, the shorter the bond, the stronger the bond COORDINATE (DATIVE COVALENT) BONDING e from the same species. - Ofter drawn with, not showing the direction in which the electrons were donated A bond where both of the electrons come! - However, once formes, co-ordinate bonds are identical to other covalent bonds WHEN ARE COORDINATE BONDS POSSIBLE? - When there is an atom that has a pair of elections initi LONE PAIR outer shell, which are e not already revolved in CAN H₂O FORM A COORDINATE BONO WITH AH'ION H₂O O OTHERATON H ELECTRON) TOTAL ELECTRONS Ex CENTRAL ATOM ELECTRON ELECTRON PAIRS BONDING PAIRS LONE PAIRS WHICH ATOM CAN DONATE! EQUATION 1:3 bonding 2 ways of showing pours H-00 I H EXPLANATION - The 6 2 8 4 2 2 Oxygen + H' Because inc LONE PAIRS ON NONCENTRAL ATOMY ALC₁₂ + Cr² bending- 'n group 6 Because each H dongles ! Because 2 Hs to bond H +J in the H₂ O molecule has 2 lone pairs of elections, H₂0¹ • oxygen one of which it can donate to the H² ion •forming AICI, Al 3 CL 3 TOTAL 6 PAIRS 3 OP 3 0 LP diamond GIANT COVALENT STRUCTURES Grant cevalent structures form when the bonds between a grant lattice is formed atoms continue indefinitely, and a NEED TO KNOW! CL-AI CL I love your coming S. MELTING + BOILING POINTS B 5.0₂ ELECTRICAL CONDUCTIVITY - Does not conduct CI NEED TO KNOW - Generally very high L • many strong covalent beads must be broken - 1 required to overcome the bonding OTHER PHYSICAL PROPERTIES I LAYER GRAMENE metals can occassenally form. Dot-cross diagram ore weful formuadiria to no free ions /delocalued e's to move through structure + DIAMONO bube form man Pos LAYERS GRAPHITE -likefoongy - as covalent bends are strong - directional, they are - diamond is the hardest substance known to man - drills, glass cuthing de CIANT COVALENT LAYERED SUBSTANCES • stoveture + (ally change Substance containing • infinite lattice of covalently bonde d atoms in 2. dimensions only to form layers. > y are hard, strong-brittle Each C atom bonded to 3 others · Spore electronis delocalized, occupies space between lager ELECTRICAL CONDUCTIVITVI - Very good conductor of electricity delocalised electrons in each plane, free to move t and carry the charge DENSITY 1.3 ↳ Used in - Much less dense than diamond, due to large distances between planes. HARDNESS bonding - Soft, as planes can slip over each other due to weate intermolecules forces + as an industrial lubricant • pencils + to overcome e through structure HIGH M&A POINTE -mony strong covalent bonds must be broker-Ich of energy required o the bonding SIMPLE MOLECULAR STRUCTURES MELTING GBOILING POINTS - Generally low -Tu I wo or more alom, covalently bonded together. The bonds strong covalent bonds within the molecule are - These molecules are held together by intermolecular forces. (weaker than covalent, but strong enough to keep substance soted / tid (liquid) B.G. HYDROGEN ₂ covalent bonds intermolecular forces Hydrogen atom, intermolecular forces are weak intermolecular forces also decrease re increasing e rapidly with distance (ofter little difference between melking and boiling points) ELECTRICAL CONDUCTIVITY - Little electrical conductivity in either selid /liquid state 4 no 100s or delocalised electrons OTHER PHYSICAL PROPERTIES Weak intermolecular hores (non-disectioral) weak, soft, crumbly METALLIC BONDING - electrostatic force of attraction between + metalions and delocalized election 1.3.3 METALLIC BOADING MELTING & BOILING POINTS - Generally quite high - strong attraction between × 10-3 & delucolied ↳ Depends on strength of metallic bonds MALLEABLE & DUCTIVE -Can be hammered into shape and pulled out into wires. 4 Also sonorous & shing. ELECTRICAL CONDUCTOns → Delocalised oute shell elections are free to the structure and carry the charge STRENGTH OF METALLIC BONDS IONTE the -↑ protons stronger bond - More delocalised e's per atom stronger bond 4 outer shell elections are delocalised -4 - 4 types of cogital structure crystal METALLIC - Smaller the ion, stronger bond uelon, become smaller, the higher charge they a -ion is smaller /higher charged <- it can attract the de localiond e's molestrand 13.4 BONDING & PHYSICAL PROPERTIES GIANI COVAL ENT f MOLECULAR Sodium sodium chloride magnesium diamond graphite ile move iodine. throughout 135 SHADES OF SIMPLE MOLECULESIONS Molecules and roas poses 2 types of election pours BONDING PAIRS (2e stored in a covalent bond) LONE PAIRS (20- in a pair not involved in These electron pairs will repel each other as Lone pairs repel me I more than bonding pairs I با WEAKEST compact and sit close to the nucleus of the central arom) ↳ This reduces the bond angles to a small extent (unually 2:5⁰) • Bond ongles exist between the 2 bonding pass of electors 18 ne pair - lone pair repulsion Work out nos of STRONGEST lone 2 ELECTRON PAIRS 2 BONDING PAIRS OLONE PAIRS LINEAR 180° Q111Q Q I 3 ELECTRON PAIRS 3 BONDING PAIRS OLONE PAIRS TRIGONAL PLANAR 120° G 4 ELECTRON PAIRS 4 BONDING PAIRS OLP TETRAMEDRAL 109.5" Q A pair - bond poir repulsion G A 1.3 bonding Q 1- bord pair repulsion bonding & lone poss as in coordinate bending Q in bending- · for as possible. (becaux 3 BONDING PAIRS TRIGONAL PYRAMIDAL 107° 2 BONDING PAIRS BENT (V-SHAPE) 118 А ILP • they are. A more I LONE PAIP Q 2 BONDING PAIRS 2LP BENT (V-SHAPE) 106.5° 01111 4 5 BONDING PAIRS CLP TRIGONAL BIRVRANIDAS 120° 0° Q SELECTRON PAIRS EG Q C Le 1040 Q 4 pails 4bp Olp A1Q 0 O Q 6 ELECTRON PAIRS; 6 BONDING PAIRS OLP 5 BONDING PAIRS ILP OF TA HEORAL DISTO0100 UTANBORAL 90° 4 GONDING PAIRS ILP TRICONAL PYRAMIDAL Q 0 11 altr SEE-SAW Q AQ TRICONAL PLANAR Q DOUBLE BONDS - Generally and there are multiple 0 atom, in the molecule NON CHARGED MOLECULE CHARGED MOLECULE CO₂ that only made single words - this change goes on Omilemley C GROUP O GROUP 4 bonding pairs are in 2 double bonds bending with 0 4• in bonding with C, us bx² BONDING PAIRS ILP BRILONAL PANAP 120° seem to occur when O is not the centralatom, 0 xo Q C O T-SHAPE 59² A Q BONDING PAIRS 2 LP SQUARE PLANAR 90° Q 0=0=0 ELECTRONEGATIVITY - the power of an I an atom to attract e pair of elections in a covolent kind the ELECTRONEGATIVE - SCALE 0-4 ELECTROPOSITIVE-atom with low electroned 0-10 - alom with high electronegalbrity } s electronegativity So GROUP s - cannot be described as electronegative, as they don't tend to form covalent bonds FLUORINE - electione one gativity value of 4.01 FACTORS AFFECTING ELECTRONEGATIVITY 。 (highest) NUCLEAR CHARGE TNC TEN 13.6 BOND POLARITY TAR VEN ATOMIC RADIO 15 LEN Increasing nudes charge, (increasing proten. proton no.), • Stronger attraction between nuclews + bonding pare of electroni SHIELDING - Increasing atomic radio, oute elections further from moulens 4 Weakes attraction between nucleus and bonding pair of electrons TREND IN ELECTRONEGATIVITY 1.3 bonding increasing - Increasing shielding. (more election shells). repulsion of outer elections by elections in inner shells 4 Weaker attraction between nucleus and bonding. pair of elections ACROSS A PERIOD Electronegativity i increases NC↑ SARS * more attrache, between nucleus and bending pair of electrons DOWN A GROUP Electronegativity. ART, ST 4 less attraction betwees nucleus and boiding pair of elections. decreases INTERMEDIATE BONDING - lonic + covalent bonding are the extremes of a continuam of bonding type 4 Differences in dectio negativity a • compound lies on this scale COVALENT BONDING • compounds containing elements of similar electione gebrity ↳s As they have a small electronegabuity diffince - quietley comodat CONIC BONDING • compounds containing elements of very different electronegathnily ↳ As they have a large see tronegativity difference (21-7) - conse POLAR COVALENT BOND (PERMANENT DIPOLED - elements in the bond have different electronegativities (03-17) - there is an unequal distribution of electrons in the bond ↳ Produces a charge suparation; dipole ends (6+ 6-) • The element with the larger electronegativity! polar compound will be the election rich (5-) and ↳ The element with the smaller electronegativity in c poter compound will be the electron deficient (5+) end in D a 4 can attract lone pairs of elections E.G S+ H + can determine where 8- CL Show direction of electron morat SYMMETRICAL MOLECULES POLAR & NON POLAR MOLECULES CI shared e cloud uneven distribution of electron density around molecule molecule (ALL BONOS IDENTICAL - A ·symmetrical LONE PAIRS) will be non-polar, even if individual bonds within the molecule are e polar The individual dipoles on the benas "cancel out", due to the symmetry of the molecule. NO NET DIRBLE MOVEMENT - NON-POLAR MOLECULE & NO 13-7 FORCES BETWEEN MOLECULES INDUCED DIPOLE-DIPOLE FORCES (VANDER WAALS / LONDEN DISPERSION) - Weakest of all intermolecular forces Present in all molecular substances HOW INDUCED D-D FORCES FORM - Electrons are constantly moving in a molecule which induces a temporary dipote - This induces a temporary dipole in a neighbouring molecule The 8- end of the dipole in one molecule, and the 8+ end of the dipole. a neighbouring molecule in attract each other FACTORS AFFECTING STRENGTH OF INDUCED ORD FORCES - ↑ size /sA of molecule, ↑ strength of • ↑otrength of • - ↑ number of election, T PERMANENT DIPOLE - DIPOLE FORCES 1/100 - Approximately - Present only in polar molecules HOW PERMANENT D-D FORCES FORM - There are polos molecules 8. 1.3 bonding S- 10.0 S+ strength of a covalent bond e permanent dipole - dipole attractions between S- directly impacts M&B prints /NOT in non- pelos molecules H-CL---H-CI 1 COVALENT INTERMOLECULAR PERMANENT ADNO FORCE MUST BE LINEAR HYDROCEN BONDING - Strangest of all intermolecular forces //10 to Approximately Vio strength of a covalent bond - Special case of permanent dipole-dipole attractions is Hatom is bonded to a very electronegative atom (N/0/F) - It is a strong intermolecular force (not a bond) lymatrate with - Common examples - HF, H₂O, NH₂ amino acid) -alcohols, carboxylic ass Acids GAES HOW HYDROGEN BONDS FORM There: s a very large values of H and N/0/5 lorge difference between the electronegativity · Hydrogen becomes. electron •deficient (5+) and ~/0/F becomes very election rich (8-) · very e - The 8+ Hydrogen atom forms an attraction with a lone pair of elections on N/0/F NH₂ H in the neil non-polar induced dipole-dipote he neighbowing mostrenade THE H-NO-H-NO MONT BELINEAR ---H-NO H COMPARING MELTING AND BOILING POINTS. WHAT TYPE OF INTERMOLECULAR FORCES? Is the molecule pola/non pol ↓ permanent 0-0 polar doesit contain H-N/H-0/ HOF YES ↓ i booding WHICH INTERMOLECULAR FORCES TO COMPARE Induced 0-10$ Induced 0-0 Induced 0-0 & Permanent 0-0 induced 0-0 & Hydroge bonding Permanent 0.0 & Hydrogen bonding Never compare strengths of 2 mccules with wody /20-0 EXAMPLE PARAGRAPH - F₁ & MP The H-bonding forces of attraction between the HE molecules IF COMPARING INDUCED D-D because the are stronger than the Induced D-D forces of attraction between the 51 molecules _molecule hova greak size /sn then the __) - These forces of attraction require more energ therefore He has a higher boiling point to overcome f