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Basic Chemistry CHAPTER 2-2

Basic Chemistry CHAPTER 2-2. Radioisotopes Heavier isotopes that are unstable and tend to decompose to become more stable

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Page 1: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Basic ChemistryCHAPTER 2-2

Page 2: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Radioisotopes

Heavier isotopes that are unstable and tend to decompose to become more stable

Page 3: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Radioactivity

Radioactivity—process of spontaneous atomic decay

What can we use this for?

Page 4: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Radioactivity

But how does this happen?

Page 5: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Radioactivity

But how does this happen?

nuclei are unstable so dissipate excess energy by emitting radiation in alpha, beta, or gamma rays

Page 6: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Radioactivity

Radiometric Dating:

Uranium 238U to 206Pb, with a half-life of

4.47 billion years 235U to 207Pb, with a half-life of

704 million years.

Carbon Carbon-14 is a radioactive

isotope of carbon, with a half-life of 5,730 years

Very short compared to other isotopes

Page 7: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Radioactivity

PhET Simulation

https://phet.colorado.edu/en/simulation/beta-decay

Page 8: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Inert Elements

Atoms are stable (inert) when the outermost shell is complete

Page 9: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Inert Elements

Atoms are stable (inert) when the outermost shell is complete

Atoms will gain, lose, or share electrons to complete their outermost orbitals and reach a stable state

Page 10: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Inert Elements

Atoms are stable (inert) when the outermost shell is complete

Atoms will gain, lose, or share electrons to complete their outermost orbitals and reach a stable state

Atoms are considered stable when their outermost orbital has 8 electrons (With exception to the first shell

Page 11: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Inert Elements

Page 12: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Reactive ElementsValence shells are not full and are unstable

Tend to gain, lose, or share electronsAllow for bond formation, which produces stable

valence

Page 13: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Molecules and Compounds

Molecule: Two or more like atoms combined chemically

Compound: Two or more different atoms combined chemically

Page 14: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Molecules and Compounds

https://phet.colorado.edu/en/simulation/build-a-molecule

Page 15: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

What are chemical reactions?What do you remember?

Page 16: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

What are chemical reactions?

Atoms are united by chemical bonds

OR

Atoms dissociate from other atoms when chemical bonds are broken

Page 17: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Chemical Bonds

Ionic vs. Covalent

https://www.youtube.com/watch?v=fHGSSV466Gk

Page 18: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Ionic Bonds

Form when electrons are completely transferred from one atom to another

IonsCharged particles

Anions - negativeCations - positiveEither donate or accept electrons

Page 19: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Ionic Bonds

+ –

Sodium atom (Na)(11p+; 12n0; 11e–)

Chlorine atom (Cl)(17p+; 18n0; 17e–)

Sodium ion (Na+) Chloride ion (Cl–)

Sodium chloride (NaCl)

ClNaClNa

Page 20: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Covalent Bonds

Atoms become stable through shared electrons

Single covalent bonds share one pair of electrons

Double covalent bonds share two pairs of electrons

Page 21: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Covalent Bonds - Example

Page 22: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Covalent Bonds - Example

Page 23: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Covalent Bonds - Example

Page 24: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Covalent vs. Ionic bonds

https://phet.colorado.edu/en/simulation/sugar-and-salt-solutions

Page 25: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Covalent vs. Ionic bonds

• https://www.youtube.com/watch?v=mHKGLawOTww

• https://www.youtube.com/watch?v=9WXTbkBGPrE

• https://www.youtube.com/watch?v=dD0Xl4acUFg

Page 26: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Polarity

Covalently bonded molecules

Page 27: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Polarity

Some are non-polarElectrically neutral

as a molecule

Some are polarHave a positive and

negative side

Page 28: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Polarity

https://phet.colorado.edu/en/simulation/molecule-polarity

Page 29: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Hydrogen bonds

Weak chemical bonds

Hydrogen is attracted to the negative portion of polar molecule

Provides attraction between molecules

Page 30: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Hydrogen bonds

Page 31: Basic Chemistry CHAPTER 2-2. Radioisotopes  Heavier isotopes that are unstable and tend to decompose to become more stable

Hydrogen bonds

How many drops of water can you fit on a penny?

Who can guess correctly??