Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

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Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8

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Alkali Metals  Group 1A elements  Alkali metals are NEVER found pure in nature; they are too reactive (ALL react with water even moisture in the air)  Metal +H 2 O metal hydroxide + H 2(g)  The reaction above very exothermic and can produce fire or explosion.  Reactivity of these elements increases down the group  Silvery appearance, soft enough to cut with knife   Also have low 1 st ionization energies.  Most reactive metal on periodic table is in this group- Cs- cesium  Fr- most unstable of the naturally occurring elements, highly radioactive Potassium, K reacts with water and must be stored in kerosene

Transcript of Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Page 1: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Unit 2: Atoms and Bonding

2.76 Periodic Table Trends:

6. Families

Textbook ch 7.7 -7.8

Page 2: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Big Idea 1: The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangements of atoms. These atoms retain their identity in chemical reactions. Students will be able to demonstrate understanding by laboratory investigation, analysis of data and creation of models.

SWBAT:• Correlate the atomic properties of

elements based on family with their chemical reactivity and physical properties

Learning Objectives:

Page 3: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Alkali Metals Group 1A elements Alkali metals are NEVER found pure in

nature; they are too reactive (ALL react with water even moisture in the air)

Metal +H2O metal hydroxide + H2(g)

The reaction above very exothermic and can produce fire or explosion.

Reactivity of these elements increases down the group

Silvery appearance, soft enough to cut with knife

Also have low 1st ionization energies. Most reactive metal on periodic table

is in this group- Cs- cesium Fr- most unstable of the naturally

occurring elements , highly radioactive

Potassium, K reacts

with water and must be stored

in kerosene

Page 4: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Alkaline Earth Metals• Alkaline earth metals are less reactive than alkali

metals• Alkaline earth metals are not found pure in nature; they

are too reactive• 1st and 2nd ionization energies low• Harder, denser , and melt at higher temp than alkali

metals– Be does not react with water or steam– Mg reacts slightly with water and more readily with

steam– Ca and below follow this pattern: Ca +H2O Ca(OH)2

+ H2(g)

Uses:– Mg = sea water, light weight alloys for

planes and trucks– Be = dark green form is Emerald. Light

blue/green from is Aquamarine.– Sr = fireworks and flares

Page 5: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Transition

Metals

Copper, Cu, is a relatively soft metal, and a very good electrical conductor.

Mercury, Hg, is the only metal that exists as a liquid at room temperature

Page 6: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Lanthanide & Actinide Seriesalso called inner transition

metals• F-block elements• Actinides:

– ALL are unstable and radioactive

• Lanthanides:– shiny- reactive

metals– readily available

thanks to technology

Page 7: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Poor Metals• Al,Ga,In,Sn,Tl,Pb,Bi,Po are poor metals.• They are not very reactive and weakly posses

properties • FYI: Note there is some debate about Po…some

resources say it’s a semimetal …American Chemical Society calls it a poor metal (acs.org) . I won’t test you on this one.

Page 8: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Properties of Metalloids or Semimetals They have properties of both metals and nonmetals.

Metalloids are more brittle than metals, less brittle than most nonmetallic solids

Metalloids are semiconductors of electricity

Some metalloids possess metallic luster

Page 9: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Silicon, Si – A Metalloid Silicon has metallic luster

Silicon is brittle like a nonmetal

Silicon is a semiconductor of electricityOther metalloids include:

Boron, B Germanium, Ge Arsenic, As Antimony, Sb Tellurium, Te

Page 10: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Nonmetals

• Nonmetals is a family on the periodic table that includes the nonmetals that didn’t already fit in a different family. (halogens or noble gas)

• Not to be confused when comparing all nonmetals to all metals by general characteristics (last PPT)

Page 11: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Nonmetals Nonmetals are poor conductors of heat and electricity

Nonmetals tend to be brittle

Many nonmetals are gases at room temperature

Carbon, the graphite in “pencil lead” is a great example of a nonmetallic element.

H 11.00797Hydrogen

Page 12: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Examples of Nonmetals

Sulfur, S, was once known as “brimstone”

Microspheres of phosphorus, P, a reactive nonmetal

Graphite is not the only pure form of carbon, C. Diamond is also carbon; the color comes from impurities caught within the crystal structure

Page 13: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Halogens (a specific type of non metal

Halogens are never found pure in nature; they are too reactive Halogens in their pure form are diatomic molecules (F2, Cl2, Br2, and I2)

Note some debate about At…some resources place it as a metal… unstable and only micrograms have been produced so extensive testing impossible!- I won’t test you on this one.

Chlorine is a yellow-green poisonous gas

Page 14: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Noble Gases (a specific type of nonmetal)

Noble gases are ONLY found pure in nature – they are chemically unreactive (mostly…see next slide)

Colorless, odorless and unreactive; they were among the last of the natural elements to be discovered Neon lights

Neon gas + electricity

Page 15: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

Noble Gases have been forced to react in lab

• In 1962 1st noble gas compound synthesized by Neil Bartlett

Today: • Xe forms three compounds:

– XeF2

– XeF4 (at right)– XeF6

• Kr forms only one stable compound:– KrF2

• The unstable HArF was synthesized in 2000.

XeF4 crystals

Page 16: Unit 2: Atoms and Bonding 2.76 Periodic Table Trends: 6. Families Textbook ch 7.7 -7.8.

References

Our textbook: Brown, Lemay et all. AP edition chemistry, 13th edition, 2015

www.sciencegeek.net/Chemistry

I modified the original PPTs to fit our needs in AP Chemistry.