1 - Bonding

Question 1

Dative Covalent Bond

Answer 1

Some molecules have a lone pair of electrons that can be donated to form a bond with an electron-deficient atom

An electron-deficient atom is an atom that has an unfilled outer orbital

Question 2

Linear

Answer 2

2 bonding pairs

0 lone pairs

180°

Question 3

Non-linear

Answer 3

2 bonding pairs

2 lone pairs

104.5°

Question 4

Trigonal Planar

Answer 4

3 pairs of electrons

0 lone pairs

120°

Question 5

Tetrahedral

Answer 5

4 pairs of electrons

0 lone pairs

109.5°

Question 6

Trigonal Pyramidal

Answer 6

3 pairs of electrons

1 lone pair

107°

Question 7

Trigonal bypyramidal

Answer 7

5 pairs of electrons

0 lone pairs

90° and 120 °

Question 8

Octahedral

Answer 8

6 pairs of electrons

0 lone pairs

90°

Question 9

Electronegativity

Answer 9

the ability of an atom to attract the pair of electrons in a covalent bond towards itself

Question 10

Factors Affecting Electronegativity

Answer 10

Nuclear charge (increase electronegativity)
Atomic radius (decrease electronegativity)
Shielding (decrease electronegativity)

Decrease in electronegativity down a group
Increase in electronegativity across a period

Question 11

van der Waal forces (london dispersion forces)

Answer 11

Uneven distribution of electrons creates an instantaneous dipole which creates an induced dipole in a neighbouring molecule

Question 12

Permanent dipole-dipole interaction

Answer 12

Difference in electronegativity leads to bond polarity
Not symmetrical so doesn’t cancel out
Delta positive and delta negative attracted towards each other

Question 13

Metallic Bonding

Answer 13

Lattice

Metal atoms lose outer shell electrons and turn into positively charged ions

Force of attraction between ions and delocalised electrons

Question 14

Ionic Lattice (crystal)

Answer 14

Giant lattice of alternating positive and negative ions held together by strong electrostatic forces

Eg. NaCl

High melting boiling points
Conducts electricity when molten

Question 15

Metallic Lattice (Crystal)

Answer 15

Positive metal ions in a regular lattice surrounded by a sea of delocalised electrons

Eg. Mg

Question 16

Simple Molecular Structure

Answer 16

Molecules held together by intermolecular forces (e.g., van der Waals or hydrogen bonding)

Eg. I2, ice

Question 17

Macromolecular (Giant Covalent)

Answer 17

Atoms bonded by strong covalent bonds in a giant 3D lattice

Diamond (carbon):
-Each carbon atom makes 4 covalent bonds in a tetrahedral structure.
-Extremely hard, very high melting point, does not conduct electricity.

Graphite (carbon):
-Each carbon makes 3 bonds, forming layers of hexagons with delocalised electrons.
-Layers held by weak van der Waals forces—can slide over each other (lubricant).
-Conducts electricity due to delocalised electrons.