Chemical Reactions Unit Conceptual Chem

How can the number of valence electrons for an atom be determined?  Count the number of electrons in the last energy level (furthest from the nucleus)

How do you draw a Lewis Dot Diagram? 1. Write the symbol of the element. 2. Go around the clock and add 1 electron at a time (eight is the max) 1. Write the symbol of the element. 2. Go around the clock and add 1 electron at a time (eight is the max)

What is the octet rule and how do atoms fulfill it?  Atoms want a complete/full outer energy level (usually 8 electrons an “octet”  They give away electrons or gain electrons (whatever is the easiest)  Atoms want a complete/full outer energy level (usually 8 electrons an “octet”  They give away electrons or gain electrons (whatever is the easiest)

How are cations and anions formed?  Cations are formed when atoms give away electrons  Anions are formed when atoms get electrons.  Cations are formed when atoms give away electrons  Anions are formed when atoms get electrons.

How do you determine the oxidation numbers?  Equal to the number of electrons an atom gives away or needs to get  It is positive when it electrons are lost and negative when they are gained  Equal to the number of electrons an atom gives away or needs to get  It is positive when it electrons are lost and negative when they are gained

How do you determine if a bond ionic or covalent?  Covalent Bonds form between two nonmetals  Ionic Bonds form between a metal and a non- metal  Covalent Bonds form between two nonmetals  Ionic Bonds form between a metal and a non- metal

How are ionic bonds formed?  Atoms transfer electrons to fulfill the octet rule  Ions are formed (one will be a cation the other an anion)  Atoms transfer electrons to fulfill the octet rule  Ions are formed (one will be a cation the other an anion)

How do you write formulas for ionic compounds? 1.Write the symbols with it’s oxidation number (from periodic table) 2.Rewrite each symbol 3.Criss-cross the oxidation numbers; the superscript of the first element becomes the subscript of the second element (drop the charge) and vice versa 1.Write the symbols with it’s oxidation number (from periodic table) 2.Rewrite each symbol 3.Criss-cross the oxidation numbers; the superscript of the first element becomes the subscript of the second element (drop the charge) and vice versa

What are the properties of ionic compounds? 1. Transfer electrons 2. Forms between metals and nonmetals 3. Form crystals 4. Solids at room temperature 5. Form ions 6. Formula Unit shows ratio of atoms 7. Conduct electricity 8. High Melting Point 1. Transfer electrons 2. Forms between metals and nonmetals 3. Form crystals 4. Solids at room temperature 5. Form ions 6. Formula Unit shows ratio of atoms 7. Conduct electricity 8. High Melting Point

What are some properties of metallic bonding? 1. Free floating valence electrons 2. Atoms are arranged in compact and orderly patterns Causes metals to be Ductile, Malleable and Good Conductors 1. Free floating valence electrons 2. Atoms are arranged in compact and orderly patterns Causes metals to be Ductile, Malleable and Good Conductors

How does a molecule differ from an atom of or a compound?  An atom is one representative of an element. They are represented by a symbol that can be found on the periodic table.  Molecules have more than one atom covalently bonded to each other. They are represented by a chemical formula.  Compounds are molecules with different kinds of atoms. * Compounds are molecules but molecules DO NOT have to be compounds!  An atom is one representative of an element. They are represented by a symbol that can be found on the periodic table.  Molecules have more than one atom covalently bonded to each other. They are represented by a chemical formula.  Compounds are molecules with different kinds of atoms. * Compounds are molecules but molecules DO NOT have to be compounds!

What information does molecular formula provide?  A molecular formula tells you which atoms are in the molecule and how many of each.  This is an exact count when dealing with molecules, unlike the ratio you get in a formula for ionic compounds  A molecular formula tells you which atoms are in the molecule and how many of each.  This is an exact count when dealing with molecules, unlike the ratio you get in a formula for ionic compounds

How are covalent bonds formed?  Covalent bonds form when atoms share electrons.  Form between non-metals  Form molecules  Formula is exact  Covalent bonds form when atoms share electrons.  Form between non-metals  Form molecules  Formula is exact

What are the properties of covalent bonds? 1. Covalent bonds form when atoms share electrons. 2. Form between non-metals 3. Form molecules 4. Liquids at room temperature 5. Formula is exact 6. Low boiling points and melting points 7. Poor conductors of electricity 1. Covalent bonds form when atoms share electrons. 2. Form between non-metals 3. Form molecules 4. Liquids at room temperature 5. Formula is exact 6. Low boiling points and melting points 7. Poor conductors of electricity

How are polar covalent bonds formed?  Forms between atoms in which electrons are shared unequally. One atom pulls harder on the electrons than the other one(s)  Polar molecules have one side that is slightly negative and the other is slightly positive.  Forms between atoms in which electrons are shared unequally. One atom pulls harder on the electrons than the other one(s)  Polar molecules have one side that is slightly negative and the other is slightly positive.

What is hydrogen bonding?  Hydrogen bonding occurs between a slightly positive hydrogen atom of one molecule and the slightly negative atom of another molecule.

What is hydrogen bonding?  Hydrogen bonding occurs between a slightly positive hydrogen atom of one molecule and the slightly negative atom of another molecule.

What causes oxidation and reduction?  Oxidation is caused when an atom loses electrons. The substance that loses electrons is called the reducing agent. The oxidation number increases.  Reduction is caused when an atom gains electrons. The substance that gains electrons is called the oxidizing agent. The oxidation number decreases.  Oxidation is caused when an atom loses electrons. The substance that loses electrons is called the reducing agent. The oxidation number increases.  Reduction is caused when an atom gains electrons. The substance that gains electrons is called the oxidizing agent. The oxidation number decreases.

What information does a chemical equation provide? 1.The reactants are the chemicals that react. 2.The products are the chemicals produced in the reaction. 3.+ separates the reactants or products. 4.  Yield, separates the reactants from the products. 5. (s) solids, (l) liquids (g) gases (aq) something is dissolved in water. 1.The reactants are the chemicals that react. 2.The products are the chemicals produced in the reaction. 3.+ separates the reactants or products. 4.  Yield, separates the reactants from the products. 5. (s) solids, (l) liquids (g) gases (aq) something is dissolved in water.

What is the function of a catalyst? They increase the rate of reaction. They lower the activation energy needed to start a chemical reaction.

What are factors that change the rate of a reaction? 1.Temperature 2.Concentration 3.Particle Size 4.Catalysts 1.Temperature 2.Concentration 3.Particle Size 4.Catalysts

What are some examples of the Law of Conservation of Mass? In a closed system the mass should remain the same; the amount of reactants will equal the amount of products regardless of physical and /or chemical changes 1.Sulfur and Copper 2.Alka-Seltzer and Water 3.Salt and water 4.Melting Ice In a closed system the mass should remain the same; the amount of reactants will equal the amount of products regardless of physical and /or chemical changes 1.Sulfur and Copper 2.Alka-Seltzer and Water 3.Salt and water 4.Melting Ice

How do you predict the products of a chemical reaction?  Use the number of elements and or compounds reacting to predict reaction type and possible products 1.Two elements or two compounds usually combine to form a single compound 2.A single binary compound or a compound with a polyatomic ion form two or more elements and or compounds 3.An element or a compound forms a different element and a new compound 4.Two ionic compounds will exchange cations to form two different compounds  Use the number of elements and or compounds reacting to predict reaction type and possible products 1.Two elements or two compounds usually combine to form a single compound 2.A single binary compound or a compound with a polyatomic ion form two or more elements and or compounds 3.An element or a compound forms a different element and a new compound 4.Two ionic compounds will exchange cations to form two different compounds