Bonding and Shapes of Molecules

Write the formula for aluminium sulfate.

Al₂(SO₄)₃

Give two examples of species containing dative covalent bonds.

Ammonium ion (NH₄⁺) and oxonium ion (H₃O⁺)

What is VSEPR theory?

Valence Shell Electron Pair Repulsion theory: electron pairs repel each other and arrange to be as far apart as possible

What is the order of repulsion strength between electron pairs?

Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding pair

How do lone pairs affect bond angles?

Lone pairs repel more strongly than bonding pairs, compressing bond angles by approximately 2.5° per lone pair

What is the bond angle and shape for 2 bonding pairs and 0 lone pairs?

Linear, 180°

What is the bond angle and shape for 3 bonding pairs and 0 lone pairs?

Trigonal planar, 120°

What is the bond angle and shape for 4 bonding pairs and 0 lone pairs?

Tetrahedral, 109.5°

What is the bond angle and shape for 3 bonding pairs and 1 lone pair?

Trigonal pyramidal, approximately 107°

What is the bond angle and shape for 2 bonding pairs and 2 lone pairs?

Bent (V-shaped), approximately 104.5°

What is the bond angle and shape for 5 bonding pairs and 0 lone pairs?

Trigonal bipyramidal, 90° and 120°

What is the bond angle and shape for 6 bonding pairs and 0 lone pairs?

Octahedral, 90°

What is electronegativity?

The ability of an atom to attract the bonding pair of electrons in a covalent bond

What is the trend in electronegativity across the Periodic Table?

Increases across a period, decreases down a group

Which is the most electronegative element?

Fluorine

Which molecules can hydrogen bond with water?

Any molecule containing N-H, O-H, or F-H bonds

What is the bond angle and shape in a water molecule?

Approximately 104.5°. Bent/ v-shaped

What is the bond angle and shape of ammonia?

Approximately 107°, Trigonal Pyramidal

What is the bond angle and shape in methane?

109.5°, tetrahedral

What’s the bond angle and shape for molecule with 4 bonding pairs and 1 lone pair?

Seesaw <120° and <90°

What’s the bond angle and shape for molecule with 2 bonding pairs and 1 lone pair?

Bent <120, approx 118

What’s the bond angle and shape for molecule with 5 bonding pairs and 1 lone pair?

Square pyramid <90

What’s the bond angle and shape for molecule with 3 bonding pairs and 2 lone pairs?

T-shape 86 <90

What’s the bond angle and shape for molecule with 4 bonding pairs and 2 lone pairs?

Square Planar, 90

What’s the bond angle and shape for molecule with 2 bonding pairs and 3 lone pairs?

Linear, 180

What’s the bond angle and shape for molecule with 3 bonding pairs and 3 lone pairs?

T- Shape <90 88

What’s the bond angle and shape for molecule with 2 bonding pairs and 4 lone pairs?

Linear, 180