Structure & Bonding

A Dative covalent bond differs from covalent- only in its formation

Because...

Both electrons of the shared pair are provided by one species (donor) & it shares the electrons with the acceptor

Donor species will have lone pairs* in their outer shells

*a pair of electrons occupying an orbital in an atom or molecule and not directly involved in bonding.

Types of Chemical Strong Bonds:

• Ionic (or electrovalent)
• covalent
• dative covalent
• metallic

Types of Physical Weak Bonds:

• van der waals forces
• dipole-dipole interaction
• hydrogen bonds

First Ionisation Energy: the energy required to remove 1 mole of electrons (to infinity) from  1 mole of atoms in gaseous state to form 1 mole of cations in gaseous state.

Equations to show Ionisation energy: use half equations with (g) state symbols

Trends:

• Ionisation energy increases as you go across a period
• Ionisation energy decreases as you go down a group

Factors that affect Ionisation energy:

• no. of protons increase=more energy
• atomic radius (size) increase=less energy (as electron is further away from nucleus-less attraction)
• more shells aka more sheilding=less energy

Electron Affinity: amount of energy released when an electron is added to a neutral atom/molecule (mostly) in the gaseous state to form an anion. Increases across period and up a group.