CHEMICAL BONDS Chapter 20

BONDING - journal Draw the BOHR ATOM & Lewis Dots for Hydrogen, Carbon, Chlorine, and Neon How many valence electrons does each have? How many more electrons does each need to be full in its valence shell? Are atoms stable when their valence shells are partially empty?

Chemical PROPERTIES depend on the number of valence electrons. BONDING Chemical PROPERTIES depend on the number of valence electrons.

BONDING Therefore, chemical BONDING and REACTIVITY (how an element reacts) depend on an element’s electron configuration.

BONDING Which families on the Periodic Table are UNSTABLE because of their electron configurations? CIRCLE THEM.

BONDING STABLE ELECTRON CONFIGURATION: Which group does this describe?

What do elements with UNSTABLE ELECTRON CONFIGURATIONS do? BONDING What do elements with UNSTABLE ELECTRON CONFIGURATIONS do?

They CHEMICALLY BOND and form compounds BONDING They CHEMICALLY BOND and form compounds IONIC BONDING

BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer Both Sodium and Chlorine are now STABLE (FULL) in their highest energy levels

What types of elements are Sodium and Chlorine? BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer What types of elements are Sodium and Chlorine?

BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer between a metal and a nonmetal.

When an atom gains or loses electrons, what does it get? BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer between a metal and a nonmetal. When an atom gains or loses electrons, what does it get? A CHARGE.

BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer between a metal and a nonmetal ION: An atom with a positive or negative CHARGE from electron transfer.

BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer between a metal and a nonmetal In the bond, one becomes positive (loses electrons) and one becomes negative (gains electrons).

WHAT DO OPPOSITE CHARGES DO? BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer between a metal and a nonmetal WHAT DO OPPOSITE CHARGES DO?

This is HOW the IONIC BOND forms. BONDING IONIC BONDING – the forming of a stable electron configuration through electron transfer between a metal and a nonmetal ATTRACT. This is HOW the IONIC BOND forms.

BONDING HOW can you predict which elements will make positive ions and which will make negative ions?

IONIC BONDING Ionization Energy: the ability to PULL ON ELECTRONS. Which side GIVES UP electrons more easily? Which side has the MOST PULL?

IONIC BONDING TELLS YOU THE OXIDATION NUMBER Ionization Energy: the ability to PULL ON ELECTRONS. TELLS YOU THE OXIDATION NUMBER Take out your Periodic Table. Predict the OXIDATION NUMBERS for A Groups

IONIC BONDING PROPERTIES OF IONIC COMPOUNDS Form between a metal and a nonmetal Brittle/crystalline High melting/boiling points Dissolve (ions come apart) in water & conduct electricity 20

IONIC BONDING NAMING IONIC COMPOUNDS This is Binary Nomenclature The metal (positive ion) goes first in the formula The nonmetal (negative ion) goes last in the formula NaCl – Sodium Chloride HF – Hydrogen Fluoride MgI2 – Magnesium Iodide KBr - ??? Potassium Bromide This is Binary Nomenclature Ionic Bonding Challenge

IONIC BONDING

BONDING – Journal 3 Show ALL THE STEPS of an IONIC BOND between a Family 1A element and a Family 7A element, between a Family 2A and Family 6A, and a Family 3A and a Family 5A.

CHEMICAL BONDS – Covalent Chapter 20

BONDING – Journal Show all of the steps needed to bond Sodium and Bromine. Show all of the steps needed to bond Magnesium and Fluorine. What is the full definition of an ionic bond? Why do elements bond? Answer the question for Figure 10 on page 166 of your book.

Chemical PROPERTIES depend on the number of valence electrons. BONDING Chemical PROPERTIES depend on the number of valence electrons.

BONDING Therefore, chemical bonding and reactivity depend on an element’s electron configuration.

BONDING STABLE ELECTRON CONFIGURATION: Which group does this describe?

What do elements with UNSTABLE ELECTRON CONFIGURATIONS do? BONDING What do elements with UNSTABLE ELECTRON CONFIGURATIONS do?

BONDING They BOND COVALENT BONDING

Both Hydrogens are now STABLE in their highest energy levels BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING Both Hydrogens are now STABLE in their highest energy levels

What type of element is Hydrogen? BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING What type of element is Hydrogen?

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS What element is this?

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How many electrons are shared in each picture?

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS Two = A PAIR This is called a SINGLE COVALENT BOND

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS Each atom shares AN EQUAL number of electrons to fill its outer shell

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS This is how you DRAW a SINGLE COVALENT BOND

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS A single line means each atom shared one electron each to get full.

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How would you show the bond between Carbon and Hydrogen? BREAK FOR THE BONDING BASICS SHEET

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How would you show the bond between Carbon and Hydrogen?

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How would you DRAW the bond between Carbon and Hydrogen?

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS What kind of bond would 2 oxygen atoms form? COVALENT

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How many electrons does each atom need? TWO

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How many TOTAL electrons are shared? FOUR

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How would you draw this? This is a DOUBLE COVALENT BOND. 2 pairs shared

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS What kind of bond would 2 nitrogen atoms form? COVALENT

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How many electrons does each atom need? Three

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How many total electrons are shared? Six (three pairs)

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How would you draw this? This is a TRIPLE COVALENT BOND 3 pairs shared

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS Sometimes electrons are NOT SHARED EQUALLY

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS This is called a POLAR COVALENT MOLECULE

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS The molecule has a negative side and positive side

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS The molecule has a negative side and positive side

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS Whenever electrons are SHARED, the thing that is formed is called a MOLECULE.

BONDING COVALENT BONDING – the forming of a stable electron configuration through electron SHARING between NONMETALS How do you write the Chemical Formula for a MOLECULE?

How do you write the Chemical Formula for a MOLECULE? BONDING How do you write the Chemical Formula for a MOLECULE? H2 O2 CH4 F2 N2

HOW DO YOU NAME A MOLECULE? BONDING HOW DO YOU NAME A MOLECULE? H2O Dihydrogen oxide CO2 Carbon dioxide CH4 Carbon tetrahydride HCl Hydrogen Chloride SO3 Sulfur trioxide

Building Covalent Molecules Number of shared electrons Name of bond Shown in a structural formula by what symbol? Shown in a model by how many of what item? 2 SINGLE ----- ONE STICK 4 DOUBLE === TWO SPRINGS 6 TRIPLE THREE SPRINGS

Building Covalent Molecules Element Color Lewis Dot Number of covalent bonds needed to get a full outer shell = number of holes C BLACK 4 H YELLOW 1 O RED 2 S SILVER 2 N BLUE 3

Building Covalent Molecules Suppose you need to make three covalent bonds to get a full outer shell. What are three ways of covalent bonding involving combinations of single, double, and triple bonds that you could use?

Building Covalent Molecules When you build a good model what happens to the holes in the atomic models? THEY ARE FULL

Liquid, clear, used for cleaning & manufacturing Molecule’s name PHYSICAL PROPERTIES Chemical Formula Structural formula water Liquid, clear, high boiling point H2O oxygen Gas, clear, low boiling point, 18% of atmosphere O2 nitrogen Gas, clear, low boiling point, 78% of atmosphere N2 methane Flammable, clear, gas CH4 propane Flammable, clear, gas C3H8 butane Flammable, clear, gas C4H10 rotten egg gas Stinks, toxic, clear H2S ammonia Liquid, clear, used for cleaning & manufacturing NH3 carbon dioxide Clear, gas, low boiling point CO2