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Chapter FourChapter FourChemical Bonding:
The Ionic Bond Model
Chapter 4 | Slide 2
Chemical Bonding: The Ionic Bond Model cont’d
Chemical Compounds• _________ Compounds
– Usually Metal and Nonmetal ions– ________ Bonds– Solids, high melting, conducts electricity (molten or in
solution)
• __________ Compounds– Usually between Atoms of same Element or between
atoms of nonmetals– __________ Bonds– Gases, liquids, or low melting solids, non-conductor
Chapter 4 | Slide 3
Chemical Bonding: The Ionic Bond Model cont’d
• What are chemical bonds?• Chemical bond: attractive _______ holding two or
more atoms together.• Ionic bond results from the attraction of ________
and ____________ ions– Usually, a metal forms the ________ ion and a
nonmetal forms the _________ ion
• Covalent bond results from _________ electrons between the atoms. – Usually found between ____________
Chapter 4 | Slide 4
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 Focus is on Ionic Bonds• Bond formed through the ________ of one or
more electrons from one atom or group of atoms to another atom or group of atoms
• Metals tend to give up electrons and form ______• Non-metals tend to accept electrons and form
_________• The Ionic Bond is formed by the attraction
between the _____ and ____ charges
Chapter 4 | Slide 5
Chemical Bonding: The Ionic Bond Model cont’d
Recall Chapter 3 Topic Electron Configurations
Electrons residing in outer most energy level are called distinguishing or valence electrons
Valence electrons determine chemical properties or how atoms of one particular element interact (give up or gain electrons) with atoms of another element
Chapter 4 | Slide 6
Chemical Bonding: The Ionic Bond Model cont’d
• Valence Electrons:– Example: Mg: ________________________– Example: Cl: ____________________________
• An easy way to determine how many valence electrons an element has:– The number of valence electrons is _______ to the
group number (for elements in the s and p blocks)
Chapter 4 | Slide 7
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 | Slide 8
Chapter 4 | Slide 9
Chemical Bonding: The Ionic Bond Model cont’d
How many valence electrons do the following elements have?– Na
– Al
– S
– Cl
Chapter 4 | Slide 10
Chemical Bonding: The Ionic Bond Model cont’d
Lewis SymbolIs the chemical symbol of an element surrounded by dots equal in
number to the number of __________ electrons present in atoms of the element
Elements in the same group have the same number of ___________ electrons
The number of __________ electrons for elements in the same group is the same as the “A” Group number
The maximum number of ____________ electrons for any element is eight (H and He exceptions)
Eight ____________ electrons is most stable and results in the rule of eight or octet rule to produce a noble gas electron configuration
Chapter 4 | Slide 11
Chemical Bonding: The Ionic Bond Model cont’d
→ Fig. 4.2 Gilbert Newton Lewis was one of the foremost chemists of the 20th century.
Edgar Fahs Smith Collection, University of Pennsylvania Library
Chapter 4 | Slide 12
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 | Slide 13
← Fig. 4.3 Loss of an electron from a sodium atom leaves it with one more proton than electrons, so it has a net electrical charge of +1.
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 | Slide 14
Chemical Bonding: The Ionic Bond Model cont’d
Fig. 4.4 a-c (a,b) Two-dimensional cross section and a three-dimensional view of sodium chloride. (c) sodium chloride crystals
Chapter 4 | Slide 15
Focus on Mg and Cl
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 | Slide 16
Chemical Bonding: The Ionic Bond Model cont’d
Let’s look at Mg. Its electron configuration is 1s22s22p63s2.– If it loses ____ electrons to become ________, it will
have the electron configuration 1s22s22p6
• ____ Valence Electrons!– If it gains ____ electrons to become ______, it will have
the electron configuration 1s22s22p63s23p6
• ___ Valence Electrons!– The question is which is easier? To lose TWO electrons
or to gain SIX?• Losing two: Therefore, Mg tends to form Mg2+ ions
Chapter 4 | Slide 17
Chemical Bonding: The Ionic Bond Model cont’d
Let’s look at Cl. Its electron configuration is 1s22s22p63s23p5.– If it loses ____ electrons to become ______, it will
have the electron configuration 1s22s22p6
• ___ Valence Electrons!– If it gains _____ electron to become ______, it will
have the electron configuration 1s22s22p63s23p6
• ___ Valence Electrons!– The question is which is easier? To lose SEVEN
electrons or to gain ONE?• Losing ONE: Therefore, Cl tends to form Cl- ions
Chapter 4 | Slide 18
Chemical Bonding: The Ionic Bond Model cont’d
• So, Mg will form Mg2+ ions, and Cl will form Cl- ions.
• Opposite charges attract:
• Mg2+ + 2Cl- MgCl2
Chapter 4 | Slide 19
Chemical Bonding: The Ionic Bond Model cont’d
Isoelectronic SpeciesAre atoms or ions that have the ______ number
and configuration of electrons.
N3- O2- F1- Na1+ Mg2+ Al3+
All are isoelectronic with ______ and all have the electronic configuration 1s2 2s2 2p6
Chapter 4 | Slide 20
Chemical Bonding: The Ionic Bond Model cont’d
Formula Units
The smallest whole number repeating ratio of ions present in an ionic compound that results in charge neutrality.
NaCl MgCl2 AlCl3
Na2O MgO Al2O3
Chapter 4 | Slide 21
→ Fig. 4.5 Cross section of the structure of the ionic solid NaCl.
Chemical Bonding: The Ionic Bond Model cont’d
E. R. Degginger/Color-Pic
Chapter 4 | Slide 22
Chemical Bonding: The Ionic Bond Model cont’d
• The number of electrons an atom loses or gains is related to its position on the periodic table.
Chapter 4 | Slide 23
Chemical Bonding: The Ionic Bond Model cont’d
• Group IA metals • Group IIA metals • Group IIIA metals • Group VIIA nonmetals • Group VIA nonmetals • Group VA nonmetals
Chapter 4 | Slide 24
Chemical Bonding: The Ionic Bond Model cont’d
→ Fig. 4.8 Periodic table in which the metallic elements that exhibit a fixed ionic charge are highlighted.
Chapter 4 | Slide 25
Chemical Bonding: The Ionic Bond Model cont’d
Writing Formulas for compounds• For compounds, a neutral species, the number of
electrons lost and gained must be _______.• The amount of positive charge must _______ the
amount of negative charge.• Formulas of ionic compounds
– Symbol for the positive ion is always written first– The charges on the ions are _______ shown in the
formula– The _____________ in the formula give the combining
ratio for the ions
Chapter 4 | Slide 26
Chemical Bonding: The Ionic Bond Model cont’d
It may be helpful to initially write in the charges of each ion, then determine the number of + and – ions that would balance out the charges.
K1+ S2-
Al3+ O2-
Chapter 4 | Slide 27
Chemical Bonding: The Ionic Bond Model cont’d
Naming Ionic Compounds• First word of name:
– Name of ___________ (first element in formula)– If the metal can form more than one _________, then
the charge is indicated in parentheses in the name. • Examples: Cu+ = copper (I); Cu2+ = copper (II).
• Second word of name:– Name of ________ (second element in formula). Write
the _____ of the name of the nonmetal ion with the –ide ending
Chapter 4 | Slide 28
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 | Slide 29
Chemical Bonding: The Ionic Bond Model cont’d
What is the name or formula for each of the following?
• K3N
• AuCl3
• PbS
Chapter 4 | Slide 30
• Chromium (III) oxide
• Iron (II) oxide
• Magnesium Chloride
Chapter 4 | Slide 31
Chemical Bonding: The Ionic Bond Model cont’d
Thus far these have been compounds formed by Metal Cations and Non-metal Anions.
An ionic compound in which one element present is a metal and the other element present is a nonmetal is called a “_________ Ionic Compound”
Chapter 4 | Slide 32
Chemical Bonding: The Ionic Bond Model cont’d
• Monatomic ion– An ion formed from a _______ atom through loss or
gain of electrons– Examples: Na+, S2-, etc.
• Polyatomic ion– An ion formed from a ______ of atoms (held together by
covalent bonds) and as a whole becomes charged through loss or gain of electrons
– Can be the positive or the negative ion in an ionic compound
Chapter 4 | Slide 33
Chemical Bonding: The Ionic Bond Model cont’d
Chapter 4 | Slide 34
Chemical Bonding: The Ionic Bond Model cont’d
• Give the formulas and names of the ionic compounds formed between the following ions:
– NH4+ & PO4
3-
– Na+ & NO31-
– NH4+ and O2-
Chapter 4 | Slide 35
– NH4+ and PO4
3-
– Li+ and CO32-
– Mg2+ and NO31-
Chapter 4 | Slide 36
Chemical Bonding: The Ionic Bond Model cont’d