Unit 3 - Chemical Bonding Flashcards
What is an anion?
A negatively charged ion
What is a cation?
A positively charged ion
Name the 3 types of intermolecular forces (van der Waals forces)
- Instantaneous dipole-induced dipole forces (id-id forces) 2. Permanent dipole - permanent dipole forces (pd-pd force) 3. Hydrogen bonding
Describe ionic bonding
The electrostatic attraction between oppositely charged ions (also called an electrovalent bond)
Describe covalent bonding
The electrostatic attraction between the nuclei of two atoms and a shared pair of electrons
What are lone pairs of electrons?
Pairs of electrons in the outer shell of an atom that are not involved in bonding
Give 4 examples of covalent compounds that do not have an octet of electrons
BF₃, SF₆, PCl₅, SO₂
What is a co-ordinate bond
The sharing of a pair of electrons between two atoms where both electrons in the bond come from the same atom. Also called a datiev covalent bond
Define bond energy
The energy required to break one mole of a particular covalent bond in the gaseous state. Units are kJ mol⁻¹
What two things do the shape and bond angles of a covalently bonded molecule depend on?
- The number of pairs of electrons around each atom 2. Whether these pairs are lone pairs or bonding pairs
Describe metallic bonding
The electrostatic attraction between positive ions and delocalised electrons
Define electronegativity
The power of an atom to attract electrons to itself
Describe polar bonds
The electron pair in the bond is drawn towards the atom with the larger electronegativity, making one end of the molecule slightly positive compared with the other
Describe instantaneous dipole-induced dipole (id-id) forces
The weakest intermoleculer force. Results from temporary instantaneous dipole induced in both polar and non-polar molecules. Also called London dispersion forces
Describe permanent dipole-permanent dipole (pd-pd) forces
Attractive intermoleculer forces which result from permanent dipoles in molecules
