Thursday's class 2-3

Thursday's class 2-3

Have out:

• Periodic table

• Electronegativity chart ​

• Lewis dot periodic table ​

By Connor Boyd

Today we will cover

• ​Ionic compound ​

• Covalent compounds

• Molecular geometry

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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..

Ionic bonding

• ​Transferring of electrons

• Formation of salts

• No actually 'bonds'. Held together by opposite charges

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Transferring of electrons from one element to another resulting in oppositely charged ions.

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Ionic Bonding

Multiple Choice

Which part of the atom is responsible for chemical bonding?

• Core Electrons

• Valence Electrons

• Protons

• Neutrons

​Recap video (optional)

• Electrons transfer from a metal to a nonmetal

• Electron transfer results in one negatively charged ion ​(anion) and one positively charged ion (cation)

​Characteristics

Ionic Bonding

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Multiple Choice

Nonmetals tend to

• gain electrons

• lose electrons

​Lewis dot periodic table shows this

Multiple Choice

Which is the correct formula for sodium chloride?

• SoCl
• SdCl
• NaCl
• NaCl₂

​Ionic bonds - Writing chemical formulas

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For Ionic bonding​

1. Cation first (+ ion)

2. Anion second (- ion)

3. Subscripts representing ratio between cation and anion

4. Check that charges balance out - Do not include charges in equation.

Multiple Choice

Ca²⁺ and N^3- create...

• Ca₂N₃

• Ca₃N₂

• CaN₃

• Ca₂N

​Ionic bonds - Writing chemical formulas

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For Ionic bonding​

1. Cation first (+ ion)

2. Anion second (- ion)

3. Subscripts representing ratio between cation and anion

4. Check that charges balance out

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Multiple Choice

Bonds formed by transferring electrons from one atom to another resulting in oppositely charged ions are

• ionic

• metallic

• non polar covalent

• covalent

Rules

1. Cation first (+)

2. Anion second (-)

3. Use chemical symbols ​

4. No charges included

5. Subscripts used to express ratio between cation and anion​ in the empirical (simpilest) formula.

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Writing chemical formulas

Multiple Choice

In the formation of an ionic bond, Nitrogen will form which of the following ions?

• N
• N^-3
• N^-5
• N⁺⁵

Multiple Choice

What is the formula for aluminum fluoride?

• AlF
• Al₂F₃
• AlF₃
• Al₃F₂

Multiple Choice

Which is the correct formula for aluminum sulfide?

• AlS

• Al₃S₂

• S₃Al₂

• Al₂S₃

Multiple Choice

The positive ions tend to _____________ electrons.

• lose

• gain

Covalent bonding and molecular geometry

Chemistry

​Have Periodic table and electronegativity chart out

​Covalent bonding

Key concepts:

• Nonmetal with a nonmetal

• Electrons are being shared

• Polar or nonpolar based on electronegativity of elements bonded

• All elements still want to fill outer shells (octet rule!) ​

Subject | Subject

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What makes this happen? - Chemical bonding

• Electronegativity is the key

• more specifically, the DIFFERENCE in electronegativity....

• ​Electronegativity is the strength that an atom can pull electrons.

Multiple Choice

Which element has a higher electronegativity value?

• Niobium

• Tin

• Cadmium

• Iodine

ELECTRONEGATIVITY

• DEN Range is the difference in electronegativity values between atoms

• Determines the type of bond

• Covalent bonds have similar electronegativities

• Ionic bonds have different electronegativities

Multiple Choice

Put these in increasing order:
C, H, and O

• H < C < O
• H < O < C
• O < C < H
• C < H < O

Sharing is Caring!

Electrons are shared

What you need to remember - Covalent bonding

• Nonmetal + Nonmetal

• Make COVALENT bonds

• Share electrons

• Low electronegativity difference

Multiple Choice

What region of the periodic table contains atoms that form covalent bonds?

• the left side
• the middle
• the right side
• top left

Multiple Choice

What two types of atoms make a covalent bond?

• 2 Nonmetals
• 1 Nonmetal and 1 Metal
• 2 Metals
• 2 Noble Gases

Covalent Compounds

• Have Lower melting and boiling points

• Tend to be flammable

• When dissolved in water they do not conduct electricity

• Soft or brittle solid

• Can also form crystals

Covalent bonding- Polar vs Nonpolar

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Polar vs Nonpolar

• A polar molecule is sharing electrons unequally (two different poles, one positive and the other negative)

• A nonpolar is sharing electrons equally (tug of war with two trucks pulling with the exact same force)

Polar vs Nonpolar

• Polar bonds have a difference in electronegativity that is equal to 0.4 or greater

• Nonpolar bonds have a difference in EN of 0.4 or less

Multiple Choice

What type of bond is I-I

• Polar

• Nonpolar

• Ionic

Molecular Polarity

• Molecular Polarity is different from the polarity of the bonds

• When a molecule is symmetrical it is nonpolar

• A nonsymmetrical molecule is polar

Multiple Choice

Is the molecule Polar or nonpolar?

• Polar

• Nonpolar

​Quiz tomorrow

​Before quiz tomorrow

We will go over the basics of molecular geometry. ​

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