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Department of Chemistry
CHEM1010 General Chemistry***********************************************
Instructor: Dr. Hong ZhangFoster Hall, Room 221
Tel: 931-6325
Email: hzhang@tntech.edu
CHEM1010/General Chemistry_________________________________________
Chapter 5. (16)-Chemical Bonds• Today’s Outline
..Review of ionic bond
..Covalent bond: Shared electron pair(s), Equal sharing ..Covalent bond: Shared electron pair(s), Unequal sharing..Covalent bond: Multiple bonds
..Names of covalent compounds or molecules..Polyatomic molecules: Water, Ammonia, and Methane..Polyatomic ions
Chapter 5. (L16)-Chemical Bonds
Building Your Chemical Vocabulary
Nitric acid: HNO3
Chock: CaSO4
Carbonic acid: H2CO3 Hydrogen peroxide: H2O2
Chapter 5. (L16)-Chemical Bonds
• Review of ionic bond ..Ionic bond typically occurs to a combination of a metal atom and a non-metal atom to form an ionic compound or molecule:
2Hg(l) + O2(g) = 2HgO(s)Hg: silvery liquid metal
O2: invisible gas
Cl2 + 2Na = 2NaCl
Cl2: greenish gas, typical non-metalNa: typical metal
Chapter 5. (L16)-Chemical Bonds
• Review of ionic bond ..Nature of ionic bond: Electrostatic attraction between cations and anions..Octet outer shell electron configuration
8 electrons in the outmost shell, most stable, the configuration of the noble gases..Octet rule: Metals tend to loose electron(s) to achieve the octet outer shall electron configuration, while non-metals tend to gain electrons to achieve the octet outer shall electron configuration. ..Only valence electron configuration is needed.
Chapter 5. (L16)-Chemical Bonds
• Covalent bond: Shared electron pair(s), equal share, nonpolar ..Non-polar covalent bond occurs to the molecules of the identical atoms:
H· + ·H = H:H = H2 one pair.. .. .. ..
:O: + :O: = :O::O: = O2 two pair .. .. .. ..
:Cl· + ·Cl = :Cl:Cl: = Cl2 one pair .. .. .. ..
..Again, only valence electron configuration is needed.
Chapter 5. (L16)-Chemical Bonds
• Covalent bond: Shared electron pair(s), equal share, nonpolar Hence, by sharing the electrons, each atom thus has an octet electron configuration. ..Covalent bond: The bond formed by a shared pair of electrons..Bonding pair: The shared pair of electrons..Nonbonding pair: The unshared pair of electrons ..Non-polar covalent bond: Both atoms have the same hold on the electrons, so the shared electrons are evenly held by each atom, no preference.
Chapter 5. (L16)-Chemical Bonds
• Covalent bond: Shared electron pair(s), unequal share, polar.. Polar covalent bond occurs to the molecules of atoms of somewhat different kinds (not strongly different), usually non-metals
.. ..H· + ·Cl: = H:Cl: one pair .. ..
H2 + Cl2 = 2HCl..Unequal sharing: Cl atom has more attraction to the electrons than H atom, more electronegative
Cl atom would have a bit more negative charge, while H atom would have a bit more positive charge
Chapter 5. (L16)-Chemical Bonds
• Covalent bond: Multiple bonds
.. ..
single bond, H:H (H2), :Cl:Cl: (Cl2) .. ..
.. ..
double bond, :O:O: (O2) .. .. .. ..
triple bond, N:::N (N2)
Chapter 5. (L16)-Chemical Bonds
• Polyatomic covalent compounds and molecules
..Water, H:O:H 8 – 6 = 2 bonds
.. ..
Ammonia, H:N:H 8 – 5 = 3 bonds ..
H
Methane, H 8 – 4 = 4 bonds ..H:C:H .. H
Chapter 5. (L16)-Chemical Bonds
• Names of covalent compounds and molecules..Common names from everyday life
water, ammonia, methane..Use of prefix
N2O4, dinitrogen tetraoxide
NO2, nitrogen dioxideNO, nitrogen oxide (nitric oxide, nitrogen monoxide)CO, carbon monoxide
CO2, carbon dioxide
SCl2, sulfur dichloride
SF6, sulfur hexafluoride
P2O5, diphosphorous pentoxide
CrO3, chromium trioxide
Chapter 5. (L16)-Chemical Bonds
• Polyatomic ions
hydroxide
.. ..
e- + ·O· + ·H = [:O:H]-
.. ..
lye, a strong base, NaOH = Na+ + OH-
..See table 5.4 on pp.135 of the textbook for more polyatomic ions, both cations and anions
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Covalent bond is formed by (a) sharing one or more pairs of protons between atoms; (b) sharing one or more pairs of neutrons between atoms; (c) sharing one or more pairs of valence electrons between atoms; (d) sharing one or more inner shell electrons between atoms.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Covalent bonds typically occur to the molecules of (a) typical metal atom(s) and typical non-metal atom(s); (b) identical atoms or atoms of somewhat different atoms; (c) any kinds of atoms; (d) none of above.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which covalent bond is polar? Is it (a) the bond between two identical atoms; (b) the bond between a non-metal atom and a metal atom; (c) the bond between two electrons; (d) the bond between two atoms that are somewhat different but not strongly different.
.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which covalent bond is non-polar? Is it (a) the bond between two identical atoms; (b) the bond between a non-metal atom and a metal atom; (c) the bond between two electrons; (d) the bond between two atoms that are somewhat different but not strongly different.
.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following molecules has covalent bond? Is it
(a) NaCl;
(b) H2O;
(c) CaO;
(d) MgCl2.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following molecules has polar covalent bond? Is it
(a) KCl;
(b) H2O;
(c) H2;
(d) Cl2.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following molecules has non-polar covalent bond? Is it
(a) AgCl;
(b) H2O;
(c) N2;
(d) HF.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following molecules has a single covalent bond? Is it
(a) AgCl;
(b) O2;
(c) N2;
(d) HF.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following molecules has a double covalent bond? Is it
(a) AgCl;
(b) O2;
(c) Cl2;
(d) HBr.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following is a polyatomic cation? Is it
(a) Br-;
(b) NO3-;
(c) NH4+;
(d) PO43-.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which of the following is a polyatomic anion? Is it
(a) Na+;
(b) SO42-;
(c) NH4+;
(d) Cl-.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right molecular formula for a covalent compound or molecule, bromine trifluoride? Is it
(a) Br3F;
(b) BrF2; (c) BrF;
(d) BrF3.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right molecular formula for a covalent compound or molecule, tetraphosphorous trisulfide ? Is it
(a) S4P3;
(b) S3P4;
(c) P3S4;
(d) P4S3.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for N2S4? Is it
(a) nitrogen sulfide;
(b) tetranitrogen disulfide;
(c) Dinitrogen tetrasulfide;
(d) non of above.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for PF5? Is it
(a) phosphorous fluoride;
(b) pentaphosphorous fluoride;
(c) phosphorous pentafluoride;
(d) non of above.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for NaNO3? Is it
(a) sodium nitrite;
(b) sodium nitrate;
(c) sodium nitrogen;
(d) nitrogen sodium.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for K2SO4? Is it
(a) potassium sulfate;
(b) potassium sulfide;
(c) potassium sulfur oxygen;
(d) dipotassium sulfur tetraoxygen.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for K2CO3? Is it
(a) potassium carbon;
(b) potassium carbonate;
(c) potassium bicarbonate;
(d) dipotassium carbon trioxygen.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for KHCO3? Is it
(a) potassium carbon;
(b) potassium carbonate;
(c) potassium bicarbonate;
(d) dipotassium carbon trioxygen.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right name for KNO2? Is it
(a) potassium nitrogen;
(b) potassium nitrite;
(c) potassium nitrate;
(d) dipotassium nitrogen dioxide.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right molecular formula for sodium bicarbonate? Is it
(a) NaCO3;
(b) Na2CO3;
(c) NaHCO3;
(d) NaCO.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right molecular formula for hydrogen sulfide? Is it
(a) HS;
(b) SH;
(c) H2S;
(d) HS2.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right molecular formula for potassium hydroxide? Is it
(a) KH;
(b) KO;
(c) HKO;
(d) KOH.
Chapter 5. (L16)-Chemical Bonds
Quiz Time
Which is the right molecular formula for calcium hydroxide? Is it
(a) CaOH;
(b) CaO;
(c) HCaO;
(d) Ca(OH)2.