Chapter 7 Ionic and Metallic Bonding 7.1 Ions 7.2 Ionic Bonds and

7.1 Ions >7.1 Ions >

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Chapter 7Ionic and Metallic Bonding

7.1 Ions

7.2 Ionic Bonds and Ionic Compounds7.3 Bonding in Metals



Valence ElectronsValence Electrons

Do Now: *THIS WILL BE COLLECTED*

1.Name 2 alkali metals.

2.Name 2 alkaline earth metals.

3.Name 2 halogens.

4.Name 2 noble gases.

5.Write down 1 thing during your break that you can relate to Chemistry.


3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved..

Coming Up

IonsIons

• Today – Sec 7.1 Ions

• Tuesday – Sec 7.2 Ionic Bonding

• Wednesday – Sec 7.3 Metals

• Thursday – Review

• Friday – Test on Chapters 6 & 7

• Next Week – Presentations begin Tuesday 11/17

6.3 Periodic Trends 6.3 Periodic Trends >>


Demonstrations

https://www.youtube.com/watch?v=xweiQukBM_k

IonsIons





Ions

IonsIons

An atom or group of atoms that has a positive or negative charge.

• Atoms become ions when electrons are lost or gained.

• Atoms can become cations or anions



Cation – ion with a positive charge•Metals tend to form cations.

IonsIons



Anion – ion with a negative charge•Nonmetals tend to form anions.

IonsIons




Valence electrons - Electrons in the highest occupied energy level of an element’s atoms. These are the electrons involved in bonding.



Electron Configurations Electron Configurations in Groupsin Groups

Determining Number of Valence ElectronsFor representative elements, the group number tells you the number of valence electrons.

• Group 1A elements have 1 valence electron

• Group 4A elements have 4 valence electrons

• Exception: Helium has only 2 valence electrons




Determining the Number of Valence Electrons for the following atoms

1. Be

2. Cs

3. F

4. O

5. Xe

6. He




Determining the Number of Valence Electrons for the following atoms

1. Be - 2

2. Cs - 1

3. F - 7

4. O - 6

5. Xe – 8

6. He - 2




Lewis Dot StructuresDiagrams that show valence electrons in the atoms of an element as dots.



Interpret Data

Electron Dot Structures of Some Group A Elements

PeriodGroup

1A 2A 3A 4A 5A 6A 7A 8A

1

2

3

4

• Notice that all the electrons within a given group (with the exception of helium) have the same number of electron dots in their structures.




Draw electron dot structures for the following atoms

1. Be

2. Cs

3. F

4. O

5. Xe

6. He




The Octet RuleThe octet rule states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas.




The Octet Rule

• An octet is a set of eight.

• Atoms of noble gases (except helium) have 8 electrons in their highest occupied energy levels and an electron configuration of ns2np6.

The octet rule states that in forming compounds, atoms tend to achieve the electron configuration of a noble gas.




The Octet Rule• Atoms of metals tend to lose their valence

electrons, leaving a complete octet in the next-lowest energy level.

• Atoms of some nonmetals tend to gain electrons or share electrons with another nonmetal atom or atoms to achieve a complete octet.



• Atoms have 1 valence electron

• Lose 1 valence electron to form cation

Na Na+ –e–

Group 1A

Formation of CationsFormation of Cations



Group 1A Cations

Both the sodium ion and the neon atom have eight electrons in their valence shells (highest occupied energy levels).





Group 2A• Atoms have 2 valence electrons.

• Lose 2 valence electrons to form a cation




• Cations of Group 1A elements always have a charge of 1+.

• Cations of Group 2A elements always have a charge of 2+.



How does a cesium atom form a cation?

A. By losing 2 electrons

B. By gaining 1 electron

C. By losing 1 electron

D. By gaining 2 electrons



How does a cesium atom form a cation?

A. By losing 2 electrons

B. By gaining 1 electron

C. By losing 1 electron

D. By gaining 2 electrons



Formation of AnionsFormation of Anions

Atoms of nonmetals and metalloids form anions by gaining enough valence electrons to attain the electron configuration of the nearest noble gas.



Chlorine atoms need one more valence electron to achieve the electron configuration of the nearest noble gas.





• All halogen atoms have 7 valence electrons and need to gain only 1 electron to achieve the electron configuration of a noble gas.

– All halide ions (F–, Cl–, Br–, and I–) have a charge of 1–.

Halide ions: ions produced when atoms of halogens gain electrons



Oxygen is in Group 6A, and an oxygen atom has 6 valence electrons.


• An oxygen atom attains the electron configuration of neon by gaining two electrons.




The name of an anion of a nonmetallic element is not the same as the element name.

– The name of the anion typically ends in -ide.

– Thus, a chlorine atom (Cl) forms a chloride anion (Cl–).

– An oxygen atom (O) forms an oxide anion (O2–).



Some Common Anions

Name Symbol Charge

Fluoride F– 1–

Chloride Cl– 1–

Bromide Br– 1–

Iodide I– 1–

Oxide O2– 2–

Sulfide S2– 2–

Nitride N3– 3–

Phosphide P3– 3–

Interpret Data



Electronegativity – ability of an atom of an element to attract electrons when the atom is in a compound.

Trends in ElectronegativityTrends in Electronegativity



END OF 7.1END OF 7.1

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Chapter 7 Ionic and Metallic Bonding 7.1 Ions 7.2 Ionic Bonds and