L2: Polarity

  • Atoms bond to form compound and attain stability

  • 3 Types of Chemical Bond

    1. Ionic Bond

    2. Covalent Bond

    3. Metallic Bond

  • Element vs. Compound

    • element has one 1 atom

    • compound has two or more atom

Diatomic Elements (elements na may subscript na 2)

  1. Hydrogen

  2. Nitrogen

  3. Flourine

  4. Oxygen

  5. Iodine

  6. Chlorine

  7. Bromine

Metalloids (Boring Silly Germans Are At The Party)

  1. Boron

  2. Silicon

  3. Germanium

  4. Arsenic

  5. Antimony

  6. Telenium

  7. Polonium

Intramolecular Force

  • intra = inside

  • forces that holds atoms together in a molecule

Ionic Bond

  • transfer of one or more valence electron from one atom to another

  • between Metal (loses electron) and Non-metal (gain electron)

  • 2 types of ions in ionic bonding: Monoatomic and Polyatomic

Monoatomic Ions

  • ion with one 1 atom

  • atom with unequal proton and electrons

  • ions can be classified as ANION or CATION

Polyatomic Ions

  • aka “molecular atoms”

  • compound is made up of two or more atoms

  • ions can be classified as ANION or CATION

Covalent Bond

  • sharing of an electron pair between atoms exist

  • NONMETAL - NONMETAL

  • Polar or Non-Polar

Polarity of Molecules

  1. Nonpolar Covalent Bond

    • bonding electron shared equally between two atoms

    • no charges on atom

  2. Polar Covalent Bond

    • bonding electron shared unequally between two atoms

    • partial charges on atom

  3. Ionic Bond

    • complete transfer of one or more valence electrons

    • full charges on resulting ions

POLAR

NONPOLAR

IONIC

bonding electron shared UNEQUALLY between two atoms

bonding electron share EQUALLY between two atoms

COMPLETE TRANSFER of one or more valence electrons

partial charges

no charges

full charges on resulting ion

Electronegativity

  • The tendency of an atom to attract electrons toward itself

  • the absolute value of the electronegativity difference between two atoms gives an idea of the type of chemical bonds that can exist between them

MEMORIZE!:

1.8 and above

IONIC BOND

0.41 to 1.79

POLAR

0 to 0.40

NONPOLAR

LEDS (Lewis electron dot structure)

  • dots: 1-2-2-3-4-5-6-7-8 (basta sa marami at sa baba 2 ang dots)

  • representation of the valence electrons of an atom that uses dots around the symbol of the element

  • octet rule = 8 valence electron

  • duet rule - hydrogen

How to determine the number of single, double, and triple bonds in an LEDS?

  1. SINGLE BOND

    • representation = single line

    • electrons = one shared pair

  2. DOUBLE BOND

    • representation = two line

    • electrons = two pairs shared (4 dots)

  3. TRIPLE BOND

    • representation = three line

    • electrons = 3 pairs shared (6 dots)

How to determine the bond type

How can you determine if an element has a low electronegativity value?

Position on the Periodic Table:

  • Group 1 (Alkali metals) and Group 2 (Alkaline earth metals) elements have low electronegativity.

  • These elements are located on the left side of the periodic table.

  • As you move from left to right across a period, electronegativity increases. Therefore, elements on the left side (e.g., sodium and magnesium) generally have lower electronegativity values.

Electronegativity Values:

  • You can also refer to the specific electronegativity values assigned to elements. These values are often found in chemistry reference materials.

  • A general rule of thumb is that elements with electronegativity values less than 2 have low electronegativity.