Download - Ionic Bonding
![Page 1: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/1.jpg)
Chapter 7
![Page 2: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/2.jpg)
Ions
• Elements within each group of the periodic table behave similarly because they have the same number of valence electrons.
• Valence electrons are the electrons in the highest occupied energy level of an elements atoms.– Valence electrons determine the chemical
properties of an element.
![Page 3: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/3.jpg)
Valence Electrons
• To find the number of valence electrons in an atom of a representative element, simply look at its group number.
![Page 4: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/4.jpg)
• In forming compounds, atoms tend to gain or lose electrons in order to achieve the electron configuration of a noble gas!!!
OctetRule
![Page 5: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/5.jpg)
Octet Rule = atoms tend to gain, lose or share electrons so as to have 8 electrons
C would like to N would like toO would like to
Gain 4 electronsGain 3 electronsGain 2 electrons
![Page 6: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/6.jpg)
Key Concept
• Atoms of metals lose their valence electrons.
• Atoms of some nonmetals ten to gain electrons or to share with other nonmetallic elements to achieve a complete octet
![Page 7: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/7.jpg)
Formation of Cations
• When an atom loses an electron it produces a positively charged ion, or a cation.
• The most common cations are those produced by the loss of valence electrons from metal atoms.
![Page 8: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/8.jpg)
Electron–Dot Structures for Ions
• Remove electrons for cations
Sodium Atomic number 11 1s22s22p63s1 1 Valence electron Na
Remove electron to form ion
Sodium Ion Atomic number 11 1s22s22p63s0 Na+
Now has full shell with similar electronic configuration to Neon --Stable noble gas configuration
![Page 9: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/9.jpg)
Formation of Anions
• The gain of negatively charged electrons by a neutral atom produces an anion.
![Page 10: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/10.jpg)
Electron–Dot Structures for Ions
• Add electrons for anions
Chlorine atomic number 17 1s22s22p63s23p5 Cl7 Valence electrons
Add electron to form ion
Chloride ion atomic number 17 1s22s22p63s23p68 Valence electrons Cl
-
Now has full shell with similar electronic configuration to Argon --Stable noble gas configuration
![Page 11: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/11.jpg)
Mg example
1s22s22p6
3s2[Ne]
3s2
Lewis Dot StructuresThe valence shell is the outermost shell of electrons of an atom.
2 electrons in the valence Shell
MgUse dots to represent Valence Electrons
![Page 12: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/12.jpg)
Electron-Dot Structures• Valence electrons represented by dots
• Electron-dot symbols– Examples: Na•, •Mg•, …
![Page 13: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/13.jpg)
Ionic Bonds
• Compounds composed of cations and anions are called ionic compounds.
• Although they are composed of ions, ionic compounds are electrically neutral.
The electrostatic forces that hold ionsTogether in ionic compounds areCalled Ionic bonds.
![Page 14: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/14.jpg)
Ionic Bonds: One Big Greedy Thief Dog!
![Page 15: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/15.jpg)
Formula Units
• A chemical formula shows the kinds and numbers of atoms in the smallest representative unit of a substance.
• Because an ionic compound exists as a collection of positively and negatively charged ions arranged in repeating patterns, its chemical formula refers to a ratio known as a formula unit.
![Page 16: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/16.jpg)
• A formula unit is the lowest whole-number ratio of ions in an ionic compound.
• For NaCl the ratio of the ions is 1:1 (one Na+ to one Cl-)
• What is the formula unit for Magnesium Chloride?
![Page 17: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/17.jpg)
Practice, Practice, Practice
• Use electron dot structures to determine formulas of the ionic compounds formed when
• 1. potassium reacts with iodine.
• 2. Aluminum reacts with oxygen.
![Page 18: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/18.jpg)
Properties of Ionic Compounds
1. Most are crystalline solids at room temperature.
2. High melting points.
3. Conduct electricity when melted or dissolved in water.
![Page 19: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/19.jpg)
Practice, Practice
• Write the formulas for each compound.
1. Barium chloride2. Lithium oxide3. Magnesium oxide4. Calcium flouride
![Page 20: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/20.jpg)
7.3 Bonding in Metals
• The valence electrons of metal atoms can be modeled as a sea of electrons.
• That is, the valence electrons are mobile and can drift freely from one part of the metal to another.
• Metallic Bonding Animation
![Page 21: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/21.jpg)
Metallic Bonds: Mellow dogs with plenty of bones to go around.
![Page 22: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/22.jpg)
Alloys
• Mixtures composed of two or more elements, at least one of which is a metal.
• Their properties are often superior to those of their component elements.
![Page 23: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/23.jpg)
Learning Check
Give the ionic charge for each of the following:A. 12 p+ and 10 e-
1) 0 2) 2+ 3) 2-
B. 50p+ and 46 e-
1) 2+ 2) 4+ 3) 4-
C. 15 p+ and 18e-
2) 3+ 2) 3- 3) 5-
![Page 24: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/24.jpg)
Learning Check
A. Number of valence electrons in aluminum1) 1 e- 2) 2 e- 3) 3 e-
B. Change in electrons for octet1) lose 3e- 2) gain 3 e- 3) gain 5
e-
C. Ionic charge of aluminum 1) 3- 2) 5- 3) 3+
![Page 25: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/25.jpg)
Solution
A. Number of valence electrons in aluminum3) 3 e-
B. Change in electrons for octet1) lose 3e-
C. Ionic charge of aluminum 3) 3+
![Page 26: Ionic Bonding](https://reader036.vdocuments.net/reader036/viewer/2022081414/54b4419b4a7959cd628b45ea/html5/thumbnails/26.jpg)
Review..
• What is a chemical bond?– Force that holds two atoms together
• What is an ionic bond?– An electrostatic force that holds
oppositely charged particles together in an ionic compound
– Forms when….?• What are atoms and compounds always
trying to achieve?– Stability– Complete set of valence electrons…