1 / 26

CHEMICAL BONDING

CHEMICAL BONDING. THEY CALL IT BONDING…CHEMICAL BONDING. Bonding Atoms. Why do atoms bond? - each atom wants a full outermost energy level - gain, lose, and share valence electrons to achieve the duet or octet rule aka: “ being happy ”

linus-rasmussen
Download Presentation

CHEMICAL BONDING

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CHEMICAL BONDING THEY CALL IT BONDING…CHEMICAL BONDING

  2. Bonding Atoms • Why do atoms bond? - each atom wants a full outermost energy level - gain, lose, and share valence electrons to achieve the duet or octet rule aka: “being happy” - gives each atom an electron configuration similar to that of a noblegas ex. Group 18: He, Ne, Ar

  3. Chemical Structure/Models • Chemical Structure/Molecular Models - arrangement of bonded atoms or ions - bond length: the averagedistance between the nuclei of two bonded atoms - bond angles: the angle formed by two bonds to the sameatom

  4. Molecular Models of Compounds • Ball and stick - atoms are represented by balls - bonds are represented by sticks * good for “seeing” angles • Structural - chemical symbols represents atoms - lines are used to represent bonds * good for “seeing” angles H H O

  5. Molecular Models Cont. • Space filling - colored circles represent atoms, and the space they take up - no bonds, no bond angles • Electron Dot/Lewis Structure - chemicalsymbol represent atom - dots represent valenceelectrons - 2 center dots represent a bond - no bond angles, no bond length

  6. Chemical Bonds • Chemical Bonds - attractive force that holds atoms or ions together - 3 types ionic, covalent, metallic - determines the structure of compound - structure affects properties - melting/boiling pts, conductivity etc.

  7. Predicting Bond Type

  8. Ionic Bonds / Ionic Compounds • Definition - bond formed by the attraction between oppositely charged ions cation: positive: lost e-’s anion: negative: gained e-’s - oppositely charged ions attract each other and form an ionic bond ex. Na+ + Cl- = NaCl - electrons are transferred from one atom to another - negative ions attract more positive ions, and soon a network is formed

  9. Properties of Ionic Compounds • Structure affects properties - strong attractions between ions: strong bonds - high melting/boiling pt - shatter when struck (think of it as one unit) - conductivity solid: ions are so close together, fixed positions, (can’t move) NO conductivity liquid: ions are freely moving due to a broken lattice structure Good conductivity

  10. Covalent Bonds • Definition - chemical bond in which two atoms share a pair of valenceelectrons - can be a single, double, or triple bond single, 2e-’s (-); double, 4e-’s (=); triple, 6e-’s( ) - always formed between nonmetals - mostly low melting/boiling points • 2 types of bonds - polar - non polar

  11. Covalent Bond Cont. • Non Polar - bonded atoms that share e-’s equally - same atoms bonded ex. Cl – Cl: Cl2 • Polar - bonded atoms that do not share e-’s equally - different atoms bonded H ex. H – N – H: NH3

  12. Metallic Bonds • Definition - a bond formed by the attraction between positively charged metalion (cation) and the sharedelectrons that surround it (sea of electrons) ex. Cu • Properties - Conductivity: Good: electrons can move freely - Malleable: lattice structure is flexible

  13. Naming Ions • Monoatomic Ions - cation -name of element with ion ex. (Na) Sodium (Na+) Sodium ion - anion - name of element with the suffix –ide ex. (Br) Bromine (Br-) Bromide • Ions with multiple cations - transition metals - most form 2+, 3+ and 4+ ex. Cu+, Cu2+

  14. Naming Metals with Multiple Ions • Transition Metals - form multiple ions - in order to name the ion use a romannumeral to indicate the charge ex. Cu2+: Copper (II), Titanium (III): Ti3+ Practice Problems: Fe3+: Iron (III) Mercury (III): Hg3+ Pb4+: Lead (IV) Chromium (II): Cr2+

  15. Polyatomic Ions • Definition - an ion made of one or more atoms that are covalently bonded and that act as a unit (atoms that have lost or gained electrons) ex. CO3 2- , NH4+ - behave the same as other ions - polyatomic ions can combined like any other ion (as a unit) ex. NH4NO3 1:1 ratio (NH4)2SO4 2:1 ratio

  16. Polyatomic Ions • Naming polyatomic ions - not logical - rules for some compounds • -ite & -ate endings - indicates the presence of oxygen - called oxyanions - if (-) does not specify how many oxygen atoms are present ex. Sulfate:4, Nitrate:3, Acetate:2

  17. Polyatomic Ions Cont. - often several oxyanions differ only in the number of oxygen atoms present ex. Sulfur - ion with more oxygen takes the –ate ending ex. SO4 - ion with less takes the –ite ending ex. SO3 • Common Oxyanions * Make sure you know these: memorize

  18. Polyatomic Ions Cont. • Common Polyatomic Ions

  19. Naming Ionic Compounds • Naming ionic compounds (binary) Formula to Name - name of cation followed by the name of the anion ex. NaCl: Sodium Chloride ZnO: Zinc (II) Oxide CuCl2: Copper (II) Chloride - formulas must indicate the relative number of cations and ions if transitional

  20. Naming Ionic Compounds • Practice Problems MgBr2 Magnesium Bromide KI Potassium Iodide CuCl2 Copper (II) Chloride Fe2S3 Iron (III) Sulfide

  21. Formulas of Ionic Compounds • Writing formulas for ionic compounds Name to Formula - balance the cation charge and anion charge, leaving NO netcharge - use subscripts to denote the number of atoms in the formula ex. NaCl: Na+ Cl- : NaCl CaCl: Ca2+ Cl- : CaCl2 **1 to 1 ratios do not designate charge** **Criss-Cross charges into subscripts**

  22. Practice Problems • Write the formula for the following atoms a. lithium oxide Li2O b. beryllium chloride BeCl2 c. titanium (III) nitride TiN d. cobalt (III) hydroxide Co(OH)3

  23. Naming Covalent Compounds • Prefix System # of atoms prefix 1 mono 2 di 3 tri 4 tetra 5 penta 6 hexa 7 hepta 8 octa 9 nona 10 deca

  24. Naming Covalent Compounds Cont. • Rules for the prefix system 1. less electronegative element is given first. It is given a prefix only if it contributes more than one atom to a molecule of the compound 2. The second element is named by combining (a) a prefix indicating the number of atoms contributed by the atom (b) the root of the name of the second element, and (c) the ending –ide 3. The o or a at the end of a prefix is usually dropped when the word following the prefix begins with another vowel ex. Monoxide or pentoxide

  25. Naming Covalent Compounds Cont. Naming covalent compounds from formula 1. SiO2 Silicon dioxide 2. PBr3 Phosphorus tribromide 3. CI4 Carbon tetraiodide 4. N2O3 Dinitrogen trioxide

  26. Writing Formulas for Covalent Compunds • Writing formulas from names • Carbon Dioxide CO2 • Dinitrogen Pentoxide N2O5 3. Triphosphorus monosulfide P3S 4. Sulfur Monobromide SBr

More Related