SASS Chem Bonding Summary

Page 1 ST ANDREW’S SECONDARY SCHOOL NAME CLASS CHEMISTRY Chemical Bonding in Substances : A Summary Bonding ⟺ Structure ⟺ Properties TEMPLATE ○1 State the structure. ○2 Describe the structure. ○3 Relate the structure to its property. Bonding COVALENT METALLIC IONIC Structure Simple molecular Giant covalent Giant metallic Giant ionic Composition Molecules Non-metallic atoms Metal atoms Ions: Anions & Cations Example CO2 / I2 Diamond / Graphite Fe / Cu NaCl / MgO Properties Melting and Boiling points / Volatility ① (substance) has a simple molecular structure. ② It consists of discrete molecules held together by weak intermolecular forces of attraction. ③ Very little energy is sufficient to overcome these forces. Hence it has low melting and boiling points. Diamond ① Diamond has a giant covalent structure. ② Each carbon atom is covalently bonded to 4 other carbon atoms in a tetrahedral arrangement, forming a continuous covalent network for its structure. ③ These strong covalent bonds require large amount of energy to overcome. Hence, it has high melting and boiling points. Graphite ① Graphite has a giant covalent structure. ② Each carbon atom is covalently bonded to 3 other carbon atoms in a giant covalent network. ③ These strong covalent bonds require large amount of energy to overcome. Hence, it has high melting and boiling points. ① (metal) has a giant metallic structure. ② It is held together by strong electrostatic forces of attraction between the positively charged cations and the ‘sea’ of delocalised electrons. ③ Large amount of energy is required to overcome these forces. Hence, it has high melting and boiling points. (exception: Hg) ① (substance) has a giant ionic structure. ② It is held together by strong electrostatic forces of attraction between the oppositely charged ions in a giant ionic lattice. ③ Large amount of energy is required to overcome these forces. Hence, it has high melting and boiling points. Melting point Boiling point HIGH LOW Strongbondingbetween particlesWeakinteractionsbetween particlesConductsElectricity? YES NO Contains mobilecharge carriersDoes not contain mobile charge carriers

Page 2 Electrical Conductivity ① (substance) has a simple covalent structure. ② It consists of discrete molecules that are electrically neutral. ③ Since it does not contain any mobile charged particles, it cannot conduct electricity. Diamond ① Diamond has a giant covalent structure. ② Each carbon atom uses all 4 of its valence electrons to form covalent bonds with 4 other carbon atoms. ③ Hence, it does not have any mobile electrons to conduct electricity. Graphite ① Graphite has a giant covalent structure. ② Each carbon atom uses only 3 out of 4 of its valence electrons to form covalent bonds with 3 other carbon atoms in a giant covalent network. ③ Hence, each carbon atom has 1 mobile valence electron that is delocalised between the layers to conduct electricity. ① (metal) has a giant metallic structure. ② It is held together by strong electrostatic forces of attraction between the positively charged cations and the ‘sea’ of delocalised electrons. ③ Hence, (metal) has mobile electrons that allows it to conduct electricity. Solid state ① (substance) has a giant ionic structure. ② In solid state, the oppositely charged ions can only vibrate about their fixed positions due to the strong electrostatic forces of attraction. ③ Thus, the ions are not mobile to conduct electricity. Aqueous / Molten state ① (substance) has a giant ionic structure. ② In aqueous/molten state, the electrostatic forces of attraction between oppositely charged ions are weakened. ③ Thus, the ions become mobile and can conduct electricity. Hardness NA Diamond Same explanation as mp & bp Graphite ① Graphite has a giant covalent structure. ② Each carbon atom is covalently bonded to 3 other carbon atoms in a giant covalent network. ③ Graphite is soft and slippery because the layers of carbon atoms are held by weak intermolecular forces of attraction and thus, can slide over each other easily. Pure metals are malleable/ ductile because the orderly layers of same-sized atoms can slide over each other easily. Same explanation as mp & bp

Page 3 Simple Molecular Structure Giant Covalent Structure Diamond Graphite Giant Metallic Structure Giant Ionic Structure 2 © UCLES 2018 0971/11/M/J/18 1 The diagrams show particles in a container. 1 2 3 Which two diagrams show the process of evaporation? A 1 o 2 B 1 o 3 C 2 o 3 D 3 o 1 2 W h i c h p i e c e o f a p p a r a t u s i s u s e d t o m e a s u r e e x a c t l y 2 6 . 3 cm3 of a liquid? ABCD 3 T h e m e l t i n g p o i n t s a n d b o i l i n g p o i n t s o f p u r e s u b s t a n c e s W , X a n d Y a r e s h o w n . W X Y melting point / °C –114 115 –101 boiling point / °C 78 445 –34 The substances are chlorine, ethanol and sulfur. Which row identifies W, X and Y? W X Y A chlorine ethanol sulfur B ethanol sulfur chlorine C sulfur chlorine ethanol D sulfur ethanol chlorine

‹8&/(6 0- >7XUQRYHU (OHPHQW;KDVSURWRQV

(OHPHQW<KDVPRUHSURWRQVWKDQ;

:KLFKVWDWHPHQWDERXWHOHPHQW<LVFRUUHFW" $<KDVPRUHHOHFWURQVKHOOVWKDQ; %<KDVPRUHHOHFWURQVLQLWVRXWHUVKHOOWKDQ; &<LVLQDGLIIHUHQWJURXSRIWKH3HULRGLF7DEOHIURP; '<LVLQWKHVDPHSHULRGRIWKH3HULRGLF7DEOHDV;

$FRYDOHQWPROHFXOH4FRQWDLQVRQO\VL[VKDUHGHOHFWURQV

:KDWLV4" $ DPPRQLD1+ %F K O R U L Q H &l &P H W K D Q H & + 'Z D W H U +2

:KLFKURZGHVFULEHVKRZDQLRQLFERQGIRUPVEHWZHHQDVRGLXPDWRPDQGDFKORULQHDWRP"

V R G L X P D W R P F K O R U L Q H D W R P $ WZRHOHFWURQVDUHORVW WZRHOHFWURQVDUHJDLQHG % RQHHOHFWURQLVJDLQHG RQHHOHFWURQLVORVW & WZRHOHFWURQVDUHJDLQHG WZRHOHFWURQVDUHORVW ' RQHHOHFWURQLVORVW RQHHOHFWURQLVJDLQHG

:KLFKGLDJUDPVKRZVWKHVWUXFWXUHRIDQDOOR\"

ABCD

‹8&/(6 0- >7XUQRYHU (OHPHQW;KDVSURWRQV

(OHPHQW<KDVPRUHSURWRQVWKDQ;

:KLFKVWDWHPHQWDERXWHOHPHQW<LVFRUUHFW" $<KDVPRUHHOHFWURQVKHOOVWKDQ; %<KDVPRUHHOHFWURQVLQLWVRXWHUVKHOOWKDQ; &<LVLQDGLIIHUHQWJURXSRIWKH3HULRGLF7DEOHIURP; '<LVLQWKHVDPHSHULRGRIWKH3HULRGLF7DEOHDV;

$FRYDOHQWPROHFXOH4FRQWDLQVRQO\VL[VKDUHGHOHFWURQV

:KDWLV4" $ DPPRQLD1+ %F K O R U L Q H &l &P H W K D Q H & + 'Z D W H U +2

:KLFKURZGHVFULEHVKRZDQLRQLFERQGIRUPVEHWZHHQDVRGLXPDWRPDQGDFKORULQHDWRP"

V R G L X P D W R P F K O R U L Q H D W R P $ WZRHOHFWURQVDUHORVW WZRHOHFWURQVDUHJDLQHG % RQHHOHFWURQLVJDLQHG RQHHOHFWURQLVORVW & WZRHOHFWURQVDUHJDLQHG WZRHOHFWURQVDUHORVW ' RQHHOHFWURQLVORVW RQHHOHFWURQLVJDLQHG

:KLFKGLDJUDPVKRZVWKHVWUXFWXUHRIDQDOOR\"

ABCD

6 © UCLES 2016 5070/11/O/N/16 9 Four gases are listed. 1 CH 4 2 NH 3 3 CO 2 4 N 2 1 mol / dm3 of each of gases 1 – 4 is allowed to diffuse. What is the order of their rate of diffusion at room temperature and pressure? slowest fastest A 1 2 4 3 B 2 1 3 4 C 3 4 2 1 D 4 1 3 2 10 Which diagram best represents the structure of a solid metal? – –– – – –– –––– – – – + + + + + + + + + + + + – ++++ –––– ++++ –––– ++++ –––– + –– – –––+ + + + + + –– – –––+ + + + + + –– –+ + + – + + + + + + – –+ – + + + + – – – – – – – – – – + + a negative ion key a positive ion an electron A C B D 11 A c o m p o u n d c o n t a i n i n g o n l y t h e e l e m e n t s c a r b o n a n d h y d r o g e n h a s 8 0 . 0 % b y m a s s o f c a r b o n . What is its empirical formula? A C3H B CH 3 C CH 4 D C2H6

‹8&/(6 0- >7XUQRYHU (OHPHQW;KDVSURWRQV

(OHPHQW<KDVPRUHSURWRQVWKDQ;

:KLFKVWDWHPHQWDERXWHOHPHQW<LVFRUUHFW" $<KDVPRUHHOHFWURQVKHOOVWKDQ; %<KDVPRUHHOHFWURQVLQLWVRXWHUVKHOOWKDQ; &<LVLQDGLIIHUHQWJURXSRIWKH3HULRGLF7DEOHIURP; '<LVLQWKHVDPHSHULRGRIWKH3HULRGLF7DEOHDV;

$FRYDOHQWPROHFXOH4FRQWDLQVRQO\VL[VKDUHGHOHFWURQV

:KDWLV4" $ DPPRQLD1+ %F K O R U L Q H &l &P H W K D Q H & + 'Z D W H U +2

7 K H D U U D Q J H P