Chapter 6: Compounds Ionic and Covalent Compounds

Chapter 6: Compounds Ionic and Covalent Compounds
Physical Science Chapter 6: Compounds Ionic and Covalent Compounds

Physical Science: Chapter 6, Compounds
Chemical Bonds A compound is a substance made of two or more elements chemically combined (bonded together). The forces that hold atoms or ions together are called chemical bonds.

Chemical Formulas A compound can be represented by a chemical formula, like CO2 The chemical formula tells you what elements are in a substance and the ratios of the elements.

Chemical Structures A chemical structure is a MODEL that shows you the elements in a compound, the ratios of the elements AND how the elements fit together

Chemical Structures structural ball-and space-filling formula stick model model

Chemical Structures & Properties The structure of a compound determines the chemical and physical properties of the compound. color viscosity flammability

Mini-Quiz #1 1). What is a chemical bond? 2). What does a chemical formula tell you about a substance? 3). What does a chemical structure tell 4). What does the chemical structure determine for a substance?

Mini-Quiz #1 (answers) 1). What is a chemical bond? The forces holding atoms or ions together. 2). What does a chemical formula tell you about a substance? The types of atoms and the ratio of atoms in the substance.

Mini-Quiz #1 (answers) 3). What does a chemical structure tell you? The types of atoms, the ratio of atoms, and how the atoms or ions are arranged. 4). What does the chemical structure determine for a substance? Chemical and physical properties

Chemical Structures & Bonding Usually atoms combine to form compounds so that each atom will have MORE stable electron configurations than the atoms would if they were alone.

Chemical Structures & Bonding Compounds can have various types of structures ionic covalent covalent networks networks molecules

Chemical Bonding There are two basic types of chemical bonding Ionic Bonding Covalent Bonding We will also briefly cover Covalent network structures Metallic bonding

Chemical Bonding: Ionic Bonding Ions are charged particles. Ions are formed when atoms transfer electrons Anions are negative ions and cations are positive ions.

Chemical Bonding: Ionic Bonding Ionic Bonds are formed when cations and anions are attracted to each other.

Chemical Bonding: Ionic Bonding ● Since metals form cations and non-metals form anions, many ionic compounds are made of metal ions and non-metal ions, like Na+Cl- to form NaCl

Monoatomic Ions Shown are the elements on the periodic table and their common charges.

Chemical Bonding: Ionic Bonding ● Often groups of atoms will bond together and transfer electrons to form a polyatomic (“many atom”) ions. hydroxide ion

Chemical Bonding: Ionic Bonding ● Polyatomic ions act as a single ion in a compound. In this example each calcium ion, Ca2+ is bonded with a carbonate ion [CO3]2-

Properties of Ionic Compounds Ionic compounds form networks called crystals, not single molecules Ammonium dichromate copper (II) sulfate

Properties of Ionic Compounds Ionic bonds are fairly strong so that ionic compounds are solid crystals (at room temperature)

Properties of Ionic Compounds Ionic bonds are fairly strong so that ionic compounds have high melting and boiling points. potassium chlorate melting point 356K

Properties of Ionic Compounds Ionic bonds are fairly strong so that ionic compounds are NOT good conductors, when solids, but ARE good conductors when melted or dissolved.

Mini-Quiz #2 1). How are cations formed? 2). How are ionic bonds formed? 3). What is a polyatomic ion? 4). List three properties of ionic compounds.

Mini-Quiz #2 (Answers) 1). How are cations formed? Atoms give up electrons 2). How are ionic bonds formed? Anions are attracted to cations 3). What are polyatomic ions? Groups of atoms bonded together acting as a single charged particle.

Mini-Quiz #2 (Answers) 4). List three properties of ionic compounds. Solid crystals, high melting points, high boiling points and good electric conductors when melted or dissolved in liquids.

Mini-Quiz #1 and 2 - Combined
1). What is a chemical bond? 2). What does a chemical formula tell you about a substance? 3). How are cations formed? 4). How are ionic bonds formed? 5). What is a polyatomic ion? 6). List three properties of ionic compounds.

Mini-Quiz #1 (answers) 1). What is a chemical bond? The forces holding atoms or ions together. 2). What does a chemical formula tell you about a substance? The types of atoms and the ratio of atoms in the substance.

Mini-Quiz #2 (Answers) 1). How are cations formed? Atoms give up electrons 2). How are ionic bonds formed? Anions are attracted to cations 3). What are polyatomic ions? Groups of atoms bonded together acting as a single charged particle.

Mini-Quiz #2 (Answers) 4). List three properties of ionic compounds. Solid crystals, high melting points, high boiling points and good electric conductors when melted or dissolved in liquids.

Chemical Bonding: Covalent Bonds Non-metal atoms (except the Noble Gases) do NOT have “enough” valence electrons (short of an octet)

Chemical Bonding: Covalent Bonds If non-metals are surrounded by other non-metal elements, they can’t transfer electrons, so they will SHARE electrons in covalent bonds.

Chemical Bonding: Covalent Bonds Sometimes non-metals atoms only need to share ONE pair of electrons, making a single covalent bond. F - F

Chemical Bonding: Covalent Bonds Sometimes non-metals atoms need to share TWO pairs of electrons, making a double covalent bond. O = O (O2)

Chemical Bonding: Covalent Bonds Sometimes non-metals atoms need to share THREE pairs of electrons, making a triple covalent bond. N Ξ N (N2)

Chemical Bonding: Covalent Bonds When two atoms of the SAME ELEMENT form covalent bonds by sharing electrons, they share electrons equally, so the bond is a non-polar covalent bond

Chemical Bonding: Covalent Bonds When two different elements form covalent bonds by sharing electrons, they do NOT share the electrons equally. ● They form a polar covalent bond (with + and - ends)

Chemical Bonding: Covalent Molecules When most atoms form covalent bonds, they form individual molecules

Chemical Bonding: Covalent Molecules Covalent molecules can be gases: carbon dioxide methane chlorine (gas) CO2 CH4 Cl2

Chemical Bonding: Covalent Molecules Covalent molecules can be liquids: water octane (in gasoline) H2O C8H18

Chemical Bonding: Covalent Molecules Covalent molecules can be solids: sucrose (sugar) C12H22O11

Chemical Bonding: Covalent Networks Covalent network solids are very strong covalent bonding situations over many atoms instead of just a pair of atoms. Non-metals in covalent networks form some of the hardest substances known. quartz crystals silicon dioxide (O-Si-O)

Chemical Bonding: Covalent Networks 1. Graphite

Chemical Bonding: Covalent Networks 2. Diamond

Chemical Bonding: Covalent Networks 3. Some interesting examples of carbon networks are called fullerenes. Buckminsterfullerene (Buckeyball) Tube fullerene

Metallic Bonds Metals that are in elemental form or bonded together have a special kind of arrangement of nuclei surrounded by valence electrons that are free to move. This is often referred to as an “electron sea” model or “pool of electrons” The electrons are said to be “delocalized”. See picture next slide

“Sea of Electrons”

Metallic Bonding It is believed that this special electron arrangement gives metals the properties that they possess, such as: Ability to conduct electricity well Malleability Ductility This is thought to be true because the “delocalized” electrons can move readily for conducting and allow the atoms to slide past each other without separating from the structure.

Mini-Quiz #3 1). How are covalent bonds formed? 2). Which types of atoms form covalent bonds? 3). What is the maximum number of shared electrons in covalent bonds? 4). What is the difference between polar and non-polar covalent bonds?

Mini-Quiz #3 5). What TWO types of substances are created with covalent bonds? 6). Why don’t Noble Gas elements (usually) form bonds? 7). Briefly define metallic bond.

Mini-Quiz #3 1). How are covalent bonds formed? By two atoms sharing electrons. 2). Which types of atoms form covalent bonds? Non-metals, except Noble Gases 3). What is the maximum number of shared electrons in covalent bonds? 6 (3 pairs of electrons)

Mini-Quiz #3 4). What is the difference between polar and non-polar covalent bonds? In non-polar bonds, the two atoms share electrons equally; in polar bonds the atoms share electrons unequally. 5). What TWO types of substances are created with covalent bonds? molecules and network covalent compounds

Mini-Quiz #3 8). Why don’t Noble Gas elements form bonds? Noble gas elements have a full “octet” of valence electrons, so they don’t need to gain, lose or share electrons to have a stable structure.

Mini-Quiz #3 6). Describe metallic bonding? Atoms sharing electrons in their outer orbitals, so loosely held electrons. 7). List three properties of metals that are caused by metallic bonding? Good conductor of electricity, ductile, malleable and tenacious.

KEY THINGS TO KNOW 1). What is a chemical bond? 2). What does a chemical formula tell you about a substance? 3). What does a chemical structure tell

KEY THINGS TO KNOW 6). How are ionic bonds formed? 7). What is a polyatomic ion? 8). How are covalent bonds formed?

KEY THINGS TO KNOW 9). Which atoms form covalent bonds? 10). What is the difference between polar and non-polar covalent bonds? 11). Which type of elements form the strongest bonds?

Chapter 6, Sections 1-2 QUIZ 1). How are ionic bonds formed? 2). Which types of atoms form covalent bonds? 3). What does a chemical formula tell you about a substance? 4). What is the difference between polar and non-polar covalent bonds?

Chapter 6, Sections 1-2 QUIZ 5). What are polyatomic ions? 6). What CAN chemical structures tell you about a compound? 7). What are the THREE types of chemical structures? 8). How do covalent bonds form? 9). What causes metallic bonding?

Chapter 6, Sections 1-2 QUIZ 1). How are ionic bonds formed? (2 pts) By the attraction between (positive) cations and (negative) anions. 2). Which types of atoms form covalent bonds? (1 pt) Non-metals (and metalloids) 3). What does a chemical formula tell you about a substance? (2 pts) The elements and the ratio of elements

Chapter 6, Sections 1-2 QUIZ 4). What is the difference between polar and non-polar covalent bonds? (2 pts) In non-polar covalent bonds the atoms share some electrons equally. 5). What are polyatomic ions? (2 pts) Groups of atoms bonded together that form an ion.

Chapter 6, Sections 1-2 QUIZ 6). What CAN chemical structures tell you about a compound? (4 pts) The elements in the compound, the ratio of elements, the bond lengths and the bond angles. 7). What are 3 types of chemical structures? (3 pts) Ball-and-stick models, space-filling models & structural formulas drawings

Chapter 6, Sections 1-2 QUIZ 8). How do covalent bonds form? (2 pts) Covalent bonds form when two atoms share electrons. 9). What causes metallic bonding?(2 pts) In metals, the outer electrons are loosely held, so they are shared between several atoms.

Chapter 6: Compounds Naming Ionic and Covalent Compounds
Physical Science Chapter 6: Compounds Naming Ionic and Covalent Compounds

Ionic Compound Formulas Ionic compound formulas show the ratio of elements in an ionic compound. For example: The chemical formula BaCl2 shows that there are two chloride ions for each barium ion in a barium chloride crystal.

Ionic Compound Formulas A single crystal of table salt has billions of ions in a crystal network so its formula could be: Na100,000,000,000 Cl100,000,000,000 We use the lowest whole number ratio for the ionic formula, so the ionic compound formula is Na1Cl1 (NaCl) This is known as an empirical formula.

Writing Formulas for Binary Ionic Compounds ● HOW DO YOU Group Group 2 KNOW THE CHARGE ON THE CATION? ● Group 1 = 1+ charge ● Group 2 = 2+ charge

Writing Formulas for Binary Ionic Compounds ● HOW DO YOU KNOW THE CHARGE ON THE CATION? ● For transition metals the ions can have different charges

Writing Formulas for Binary Ionic Compounds ● So, for transition metals you have to be told what the charge is using Roman numerals. Examples: Cr (I) or Cr (II) Cu (I) or Cu (II) Mn (II), Mn (IV), or Mn (VII) Fe (II) or Fe (III)

Writing Formulas for Ionic Compounds ● HOW DO YOU KNOW THE CHARGE ON anions? ● Non-metals in Group 15 (N, P) can form 3- anions ● Non-metals in Group 16 (O, S) can form 2- anions ● Non-metals in Group 17 (F, Cl, Br, I) can form 1- anions

Ionic Compound Formulas Ionic compound formulas have to “balance.” They must have the same number of positives (+’s) as negatives (–’s) in the total formula (total equal to zero) Examples: Na1+Cl (1+ and 1-) = 0 Ba2+S (2+ and 2-) = 0

Writing Formulas for Binary Ionic Compounds Write the formula for sodium chloride STEP 1: Write the symbol for the cation Na STEP 2: Write the charge for the cation Na+

Writing Formulas for Binary Ionic Compounds Write the formula for sodium chloride STEP 3: Write symbol for the anion Na+Cl STEP 4: Write the charge for the anion Na1+Cl1-

Writing Formulas for Ionic Compounds Write the formula for sodium chloride STEP 5: Balance the charges with subscripts Na11+Cl11- (if subscripts are 1, they are not shown in the formula) NaCl

Ionic Compound Formulas Helpful technique for balancing ionic formulas: “cross multiply” using the exponents to get the subscripts. Example: Ba2+ Cl 1- To balance: Ba1 Cl2 (We don’t show subscript 1’s) so BaCl2

Writing Formulas for Binary Ionic Compounds Write the formula for calcium fluoride STEP 1: Write the symbol for the cation Ca STEP 2: Write the charge for the cation (look on the Periodic Table) Ca2+

Writing Formulas for Binary Ionic Compounds Write the formula for calcium fluoride STEP 3: Write symbol for the anion Ca2+F STEP 4: Write the charge for the anion (look on the Periodic Table) Ca2+F1-

Writing Formulas for Binary Ionic Compound Write the formula for calcium fluoride STEP 5: Balance the charges with subscripts Ca12+F21- (if subscripts are 1, they are not shown in the formula) CaF2

Ionic Compound Formulas PRACTICE: Write formulas for: 1). magnesium bromide 2). potassium oxide 3). calcium chloride 4). strontium fluoride 5). aluminum (3+) sulfide

Ionic Compound Formulas PRACTICE: Write formulas for: 1). magnesium bromide MgBr2 2). potassium oxide K2O 3). calcium chloride CaCl2 4). strontium fluoride SrF2 5). aluminum sulfide Al2S3

Writing Formulas for Polyatomic Ionic Compounds Write the formula for potassium sulfate STEP 1: Write the symbol for the cation K STEP 2: Write the charge for the cation (look on the Periodic Table) K1+

Writing Formulas for Polyatomic Ionic Compounds Write the formula for potassium sulfate STEP 3: Write symbol for the anion (look on the Common Ions chart) K1+ (SO4) STEP 4: Write the charge for the anion K1+ (SO4)2-

Writing Formulas for Polyatomic Ionic Compounds Write the formula for potassium sulfate STEP 5: Balance the charges with subscripts K21+(SO4)12- (if subscripts are 1, they are not shown in the formula) K2(SO4)

Ionic Compound Formulas Examples: Na1+(NO3) (1+ and 1-) = NaNO3 Sr2+(CO3) (2+ and 2-) = SrCO3 Na1+(O) (2x(1+)) + 2-) = Na2O Mg2+F (2+ + 2x(1-)) = MgF2 Ca2+(PO4)3 (3x(2+) + 2x(3-)) = Ca3(PO4)2

Ionic Compound Formulas Write the formula for aluminum sulfate. Write the formulas and charges. Al 3+ (SO4) 2- 2. “Cross multiply” the exponents Al2 (SO4)3 to get the subscripts for the ions.

Ionic Compound Formulas: Practice Problems 1). Barium carbonate 2). Lithium sulfate 3). Sodium nitrate 4). Potassium phosphate 5). Strontium phosphate

Ionic Compound Formula: Practice Problems: 1). Barium carbonate Ba CO3 2). Lithium sulfate Li2SO4 3). Sodium nitrate NaNO3 4). Potassium phosphate K3PO4 5). Strontium phosphate Sr3(PO4)2

Mini-Quiz #4 1). What 2 things do ionic formulas show? 2). Write formulas for these compounds: a). potassium fluoride b). magnesium oxide c). barium nitrate d). copper (I) sulfate

Mini-Quiz #4 1). What 2 things do ionic formulas show? The elements in the compound and the RATIO of the elements. 2). Write formulas for these compounds: a). potassium fluoride KF b). magnesium oxide MgO c). barium nitrate Ba(NO3)2 d). copper (I) sulfate Cu2(SO4)

Naming Binary Ionic Compounds Step 1: Say the name of the cation for NaCl the metal ion Na+ is the cation so say “sodium” first for BaI2 the metal ion Ba2+ is the cation so say “barium” first

Naming Binary Ionic Compounds Step 2: Say the “root” name of the anion for NaCl the non-metal ion Cl1- is the anion so say “chlor-” second For BaI2 the non-metal ion I1- is the anion so say “iod-” second “barium iod- …”

Naming Binary Ionic Compounds STEP 3: Add “ide” to the anion root name NaCl is “sodium chlor … ide” BaI2 is “barium iod … ide”

Naming Polyatomic Ionic Compounds Say the name Say the name of of the cation the polyatomic anion “potassium carbonate” K2 (CO3) “barium nitrate” Ba(NO3)2 “copper (II) sulfate” Cu(SO4) “aluminum phosphate” Al(PO4)

Mini-Quiz #5 1. Name the following ionic compounds: a). NaBr, e). Li2(SO4) b). K(NO3), f). Fe(CH3CO2)3 c). Mg(OH)2, g). Co(CN) d). Cu(CO3), h). Sr(HCO3)2

Mini-Quiz #5 2). Write the formulas for the following ionic compounds: a). strontium chloride b). barium nitrate c). iron (II) iodide d). silver carbonate e). magnesium sulfate

Mini-Quiz #5 (Answers) 1. Name the following ionic compounds: NaBr, sodium bromide K(NO3), potassium nitrate Mg(OH)2, magnesium hydroxide Cu(II)(SO4) copper (II) carbonate

Mini-Quiz #5 (Answers) 1. Name the following ionic compounds: Li2(SO4) lithium sulfate Fe(CH3CO2) iron (III) acetate Co(CN) cobalt (I) cyanide Sr(HCO3) strontium hydrogen carbonate

Mini-Quiz #5 (Answers) 2). Write the formulas for the following ionic compounds: a). strontium chloride SrCl2 b). barium nitrate Ba(NO3)2 c). iron (II) iodide FeI2 d). silver carbonate Ag2(CO3) e). magnesium sulfate Mg(SO4)

Covalent Molecule Formulas: Molecular formulas are NOT just ratios like the empirical formulas for ionic compounds. Molecular formulas state EXACTLY how many atoms of each element are in the molecule. Example: Glucose (C6H12O6) has: 6 carbon, 12 hydrogen & 6 oxygen atoms

Covalent Molecule Formulas: There are millions of compounds made with covalent bonds. In Physical Science we will only deal with the formulas and names of the simplest types. In this Chapter we will learn formulas and names for binary molecules

Covalent Molecule Names: These compounds will contain two nonmetals For binary covalent molecules’ names: a). List the elements in the compound b). Say how many of each element are in the compound.

Covalent Molecule Names: To say the number of atoms, chemists use the following numbering system: mono = 1 hexa = 6 di = 2 hepta = 7 tri = 3 octa = 8 tetra = 4 nona = 9 penta = 5 deca = 10 *Note: Mono is not usually used for the first element in a covalent compound.

Naming Covalent Molecules: Step 1: Say how MANY atoms of the FIRST element are in the formula. Step 2: Say the NAME of the FIRST element Step 1: Step 2: Example: CO2 mono* carbon * If there is only ONE atom of the first element, the “mono” is usually dropped.

Naming Covalent Molecules: Step 3: Say how MANY atoms of the SECOND element are in the formula. Step 4: Use the “root” of the second element’s name, but end in “ide”. Step 3: Step 4: Example: CO di ox -ide (mono) carbon diox-ide or just carbon dioxide

Mini-Quiz #6 1). Write the FORMULA for the following: a). Sulfur dioxide b). Carbon tetrachloride c). Diphosphorus hexafluoride d). Dinitrogen pentoxide

Mini-Quiz #6 2). Write the NAME for the following: a). N2O3 b). SCl6 c). P4O10 d). PF5

Mini-Quiz #6 (Answers) 1). Write the FORMULA for the following: a). Sulfur dioxide SO2 b). Carbon tetrachloride CCl4 c). Diphosphorus hexafluoride P2F6 d). Dinitrogen pentoxide N2O5

Mini-Quiz #6 (Answers) 2). Write the NAME for the following: a). N2O3 dinitrogen trioxide b). SCl6 (mono) sulfur hexachloride c). P4O10 tetraphosphorus decoxide d). PF phosphorus pentafluoride

KEY THINGS TO KNOW 1). Why are ionic formulas empirical formulas? 2). What kinds of formulas can covalent compounds have? 3). What kind of ions will metals form? 4). What ions will non-metals form? 5). Be able to NAME ionic compounds from their formulas.

KEY THINGS TO KNOW 6). Be able to write ionic formulas from the names of the ionic compounds. 7). Be able to NAME molecules from their formulas. 8). Be able to write molecular formulas from the names of the compounds.

KEY THINGS TO KNOW 10). Know the prefixes for 1-10 in naming molecules. 11). Have a list of common polyatomic ions & silver, zinc and aluminum. 12). Know how to find the charges on metal ions in Groups 1 & 2 and non- metal ions in Groups 15, 16 & 17.

Chapter 6, Section 3 QUIZ 1). What kinds of formulas can covalent compounds have? 2). What kind of ion do metals form? 3). When naming molecules, what is the prefix for: a). 2 b). 4 c). 6 d). 8 4). What is the difference between empirical and molecular formulas?

Chapter 6, Section 3 QUIZ 5). Write FORMULAS for the following a). silver nitrate b). potassium fluoride c). barium sulfate d). strontium carbonate 6). Write the NAME for the following a). Na(OH) b). FeCl3 c). Al(NO3)3 d). CuO

Chapter 6, Section 3 QUIZ 7). Write FORMULAS for the following: a). carbon tetrachloride b). tetraphosphorus decoxide c). dinitrogen pentoxide d). sulfur dioxide 8). Write the NAME for the following: a). NO b). OCl c). CO d). FCl e). SBr2

Chapter 6, Section 3 QUIZ (Answers) 1). What kinds of formulas can covalent compounds have? (2 pts) Molecular AND empirical 2). What kind of ion do metals form?(2 pts) CATIONS 3). When naming molecules, what is the prefix for (1 pt ea) a). 2 di b). 4 tetra c). 6 hexa d). 8 octa

Chapter 6, Section 3 QUIZ (Answers) 4). What is the difference between empirical and molecular formulas?(2pts) Empirical formulas show ONLY the ratio of elements, molecular formulas show ALL the elements in the compound. 5). Write FORMULAS for the following (2 pts ea) a). silver nitrate Ag(NO3) b). potassium fluoride KF c). barium sulfate Ba(SO4) d). strontium carbonate Sr(CO3)

Chapter 6, Section 3 QUIZ (Answers) 6). Write the NAME for the following (2 pts ea) a). Na(OH) sodium hydroxide b). FeCl iron (III) cloride c). Al(NO3) aluminum nitrate d). CuO copper (II) oxide 7). Write FORMULAS for the following: (2 pts ea) a). carbon tetrachloride CCl4 b). tetraphosphorus decoxide P4O10 c). dinitrogen pentoxide N2O5 d). sulfur dioxide SO2

Chapter 6, Section 3 QUIZ 8). Write the NAME for the following: (2 pts ea) a). NO3 nitrogen trioxide b). OCl6 (mon)oxygen hexachloride c). CO carbon monoxide d). FCl7 (mono) fluorine heptachloride e). SBr2 (mono)sulfur dibromide

Chapter 6: Compounds Ionic and Covalent Compounds

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