Elements and Chemical Bonds

Elements and Chemical Bonds
Chapter 11 Material on Midterm

Essential Questions How is an electron’s energy related to its distance from the nucleus? Why do atoms gain, lose, or share electrons? How do elements differ from the compounds they form? What are some common properties of a covalent compound? Why is water a polar compound? What is an ionic compound? How do metallic bonds differ from covalent and ionic bonds?

Section 1: Electrons and Energy Levels
The three main regions of elements on the periodic table are ______________ ________________ _________________ Atoms of different elements chemically combine and form _______________ Metals Nonmetals Metalloids compounds

Combining Atoms through Chemical Bonding Most atoms hate being alone…so they form __________________! Term: Chemical bonding is the ________________ of atoms to form molecules or ionic compounds Properties of new substance are _______________ that the properties of the old substance Chemical bonds combining different

= C6H12O6 aka glucose

Combining Atoms Through Chemical Bonding It’s all about the electrons Electrons farthest from the nucleus have the greatest amount of energy When bonds form, electrons can… …be ______________ …be _____________ …be ________ shared gained lost

Review: How do I know how many electrons a neutral atom has? Same as its ________________________(proton #) Ex: chlorine atomic number

Review: Where are the electrons? 8 2 1

Outer-Level Electrons and Bonding Only the _________________ electrons are involved in forming chemical bonds valence (outermost)

Electron Dot Diagrams Aka _______________ Show __________________(and possible __________) Steps Identify the element’s group number on the periodic table Identify the number of valence electrons Draw the electrons as dots (N N E S W E S W) Determine if stable or how many bonds can form Stable: All electrons are paired Bonds possible: Each unpaired electron is a bonding site

Review: Valence Electrons and the Periodic Table Elements in the same __________ have the same number of ___________________________(generally) If Lithium has 1…then Sodium, Potassium, rubidium, Cesium, and Francium all have…___! group valence electrons 1

Draw electron dot diagrams for the valence electrons!
He, Ne, Ar Stable elements? 1 bond possible? 2 bonds possible? 3 bonds possible? 4 bonds possible? H, Li, Na, K, F, Cl Be, Mg, O, S B, Al, N, P C

To Bond or Not to Bond Not all atoms bond the _______ WANNA GET TO 8! Group 18 already has ____ (except He), so they’re happy and DO NOT REACT same 8

To Bond or Not to Bond Filling the Outermost Level Less than 8? More likely to ___________. Will share, take, or lose electron(s) to get to the magic number What about 2? _________ elements (H, He, Li, Be), will try to get to ___ electrons for that first shell Will share, take, or lose electron(s) to get to this number react 2 small

Writing Prompt #1 (of 3) Write the answer on p 62.
How do you determine the number of outer electrons for an atom? Explain how you know if an atom is likely to form bonds

Section 2: Compounds, Chemical Formulas, and Covalent Bonds
What are Covalent Bonds A covalent bond forms when two atoms __________ one or more pairs of valence electrons Occurs between ________________ Helps them get to their MAGIC NUMBER (8 or 2) share nonmetals

Covalent Bonds and Molecules Easier way to draw them– _______________ Diagrams Remember, only the valence electrons are important for bonding! Electron-Dot

Types of covalent bonds Single bonds share only ___ pair of valence electrons Double bonds share _____ pairs of valence electrons Stronger than single bonds Triple bonds share _________ pairs of valence electrons

How to draw covalent molecules using electron dot diagrams Combine the elements where they can share electrons so each have a full outer shell. (The shared electrons are the covalent bond) Examples: Hydrogen + Chlorine Fluorine + Fluorine Water Oxygen + Oxygen

Atom v. molecule Atom Molecule ______ type of element _____ or more types of elements Smallest particle into which an ____________ can be divided and still be the same element Smallest particle into which a covalently bonded _____________ can be divided and still be the same compound One Two element compound

Covalent Bonds and Molecules A molecule is the smallest unit of a substance that keeps all the physical and chemical ______________ of that substance 2 or more atoms joined in a definite ratio properties

The Simplest Molecules Must have at least two covalently bonded atoms 2 of the same element? ________________ molecules Remember: HONClBrIF Hydrogen Oxygen Nitrogen Chlorine Bromine Iodine Fluorine Diatomic

Polar v. Nonpolar molecules Electrons are not always shared evenly In a ___________ molecule, a partial positive end and a partial negative end exist because of unequal sharing of electrons Affects properties of substances (“like dissolves like”) ______________ molecules have electrons shared evenly polar Nonpolar

A chemical formula is a group of __________________________ and _____________ that represent the elements and the number of atoms of each element that make up the compound Chemical formulas and molecular models provide information about molecules chemical symbols numbers

You will use element symbols and subscripts Symbol: which element Coefficient: how many atoms of each compound Must distribute to all elements We multiply for distributing Subscript : how many of each Must distribute to element BEFORE it We still multiply for distributing

Rules: Prefix + name Prefix + name –ide Rule: Do NOT use mono- on the first element Prefixes Used in Covalent Chemical Names Mono Hexa Di Hepta Tri Octa Tetra Nona Penta Deca

Examples: CO CO2 C2H4 P2O5 N3P6 Examples: Dinitrogen monoxide Sulfur trifluoride Phosphorus pentachloride Nitrogen monoxide Tetranitrogen monoxide

Draw and name! 3 Hydrogen and 1 Nitrogen Sulfur and 2 fluorine

Section 3: Ionic and Metallic Bonds
All you need to know about ionic bonding is right here

Forming Ionic Bonds An ionic bond is an attraction between positively and negatively charged ions in an ionic compound Electrons are_________________ This creates ions, which are atoms that are no longer electrically neutral because they have gained or lost valence electrons ___________ particles As a result of an ionic bond, either _________ or ______________ ions can form transferred charged positive negative

Summary:

Forming Positive ions Positive ions (cations) form when ________ atoms _______ electrons Na loses one electron---Na+ Sodium cation Ca loses two electrons –Ca2+ Calcium cation By losing electrons, metals can get to the ________ _________! Usually 8, could be 2 metal lose magic number

Forming Negative Ions Negative ions (anions) form when ____________ atoms ______ electrons Change ending to “ide” Cl gains one electron – Cl- Chloride anion O gains two electrons – O2- Oxide anion By gaining electrons, nonmetals can get to the ____________________! Usually 8, could be 2 nonmetal gain magic number

Predicting Ionic bonds
An ionic bond would / wouldn’t form with aluminum and sodium because… An ionic bond would / wouldn’t form with Aluminum and oxygen because…

Predicting Ionic bonds
An ionic bond would / wouldn’t form with sulfur and oxygen because… An ionic bond would / wouldn’t form with sulfur and neon because… An ionic bond would / wouldn’t form with sodium and neon because…

Ionic Compounds When ionic bonds form, the number of electrons ________ by the metal EQUALS the number of electrons ____________ by the nonmetals Everyone is _________! The overall compound is neutral because the ions _________________ When ions bond, they form a repeating 3D pattern called a _____________________ lost gained happy cancel out crystal lattice

Full sentences for full credit!
Writing Prompt #2 (of 3) Write the answer on your green sheet. What is the difference between how metals and nonmetals form ions? Even though positive and negative ions are formed, why is an atom overall neutral? Full sentences for full credit!

The Trick to figuring out how many is… ___________________________________ Criss-Cross Applesauce

Criss…cross…applesauce? Mg Cl- Mg Cl MgCl2

Writing Ionic Compounds
Write the metal with its charge Write the nonmetal with its charge Criss- Cross the charges Only bring down the #, NOT the charge Examples: Sodium and Chlorine Barium and Fluorine Potassium and Oxygen Lithium and Sulfur

Naming Ionic Compounds
-ide Name of Metal + nonmetal w/ ending ______ Examples: Sodium and Chlorine Barium and Fluorine Potassium and Oxygen Lithium and Sulfur

Write and name me! Lithium and oxygen Aluminum and phosphorus
Magnesium and fluorine Calcium and sulfur

When ions bond, they form a repeating 3D pattern called a ____________________ crystal lattice

Name and Draw! Sodium and sulfur Aluminum and Iodine

Metals have properties like malleability and ductility because of their ___________________ ______________________ are bonds formed when many metal atoms share their pooled valence electrons Metals surrounded in a “sea of _____________” special bonds Metallic bonds electrons

Properties of Metals Conducting Electric Current Valence electrons that are __________ Reshaping Metals Electrons free to move around…makes it easy to shape ____________ ________________ Bending without breaking Electrons can ________ in response to pressure so they can bend without breaking moving Ductility Malleability move

Full sentences for full credit!
Writing Prompt #3 (of 3) Write the answer on your green sheet. How do metallic bonds explain ductility and malleability in metals? Full sentences for full credit!

Elements and Chemical Bonds

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