Announcements

• ​Quiz moved to Friday

• Activity planned moved to next Friday ​

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• Atomic structure

  • Protons, electrons, neutrons, energy levels​

• ​Periodic table

  • Isotopes, atomic mass, atomic number, electronegativity , empirical vs molecular formula

• Molecular geometry ​

• Ionic compounds

  • Writing chemical formulas and characteristics

• Covalent compounds

  • Polarity and characteristics ​

​Topics

Quiz Friday will cover..

Today we will cover

• ​Empirical formulas

• ​Isotopes

• ​Atomic mass

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​MOLECULAR FORMULA

​The Octet Rule is important in predicting the chemical formula of simple binary covalent molecular compounds.

Atomic Mass and Mass Number

Module 3 - Physical Science

Atomic Number, Atomic Mass and Isotopes

Review

• Atomic Mass = Protons + Neutrons

• We round the atomic mass to the nearest whole number, 4

• Since we already determined that Helium has two protons, that means: 4=2+Neutrons

• There must be 2 Neutrons in one atom of Helium

Isotopes

• atoms with the SAME number of PROTONS but DIFFERENT number of NEUTRONS

Carbon 12

Consider the Atom Carbon, the atomic number tells us the number of protons.

How many protons in Carbon 12?

Lithium isotopes

What do you notice with these 3 isotopes of Lithium?

Today's Concepts

​Introduction to empirical formula, atomic mass and Isotopes

If you are do not fully understand any of these concepts, ask questions!

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On the back table there is practice problems​

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