Wednesday's class 2-2

Wednesday's class 2-2

By Connor Boyd

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.

Multiple Choice

What is the empirical formula for C₄H₆?

• CH

• CH₃

• C₂H₃

• C₄H₆

Multiple Choice

What is the empirical formula for N₂S₃?

• NS

• N₃S₂

• N₂S₃

• N₁S_1.5

Multiple Choice

What is the empirical formula of a substance with the molecular formula C₂H₄?

• C₂H₂

• C₂H₂

• C₁H₁

• CH₂

Atomic Mass and Mass Number

Module 3 - Physical Science

Atomic Number, Atomic Mass and Isotopes

Multiple Choice

How many neutrons are there in one atom of magnesium?

• 12

• 6

• 24

Multiple Choice

What is the atomic number of this atom?

• 1
• 3
• 4
• 7

Multiple Choice

What is the atomic mass defined as?

• the number of protons
• the number of protons and neutrons
• the number of neutrons
• the number of protons and electrons

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?

Multiple Choice

What is the correct definition for isotopes?

• atoms with the same number of protons and neutrons

• Atoms with the same number of protons but different number of neutrons

• Atoms with the same number of neutrons but different number of protons

• Atoms with no mass

Lithium isotopes

What do you notice with these 3 isotopes of Lithium?

Multiple Choice

What is the difference between these 3 Lithium isotopes?

• no difference

• they have the same atomic number

• they have the same mass number and atomic number

• they have different mass numbers

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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