Structure, bonding and equilibrium

When does ionic bonding occur?

Occurs in compounds in which constituent elements have a relatively large difference in electronegativity

Ionic bonding

Transfer of electrons from one atom to another

Electronegativity

Ability of an atom to attract an electron to itself

Driving force behind ionic bonding

Lower the energy of the system

What happens when the no. protons increases moving left to right

Nuclear charge increases

What does effective nuclear charge increase?

Attraction between nucleus and electron which causes ionisation energy to increase

What happens to I.E down the periodic table?

Decreases, because principle quantum number increases as electrons spend time further away from nucleus.

Attraction is less so its easier to remove an electron

Why is there a significant increase in I.E when electrons are removed from a lower shell?

There is a significantly higher no. protons than electrons → electrons are much closer to the nucleus

Electron Gain Enthalpy

Process is normally exothermic

Normally sufficient attraction between the nucleus and the ‘new’ electron to overcome electron-electron repulsion

Trends in electron gain enthalpy

Trend reflects same arguments in Zeff and in pairing energy

Trends in Lattice enthalpy

Decreases as ion size increases

Greater charge (on either ion) greater the lattice enthalpy

When forming multiple positively charged ions the penalty for the ionisation energy is higher than the first I.E → gain in lattice enthalpy is normally much higher

Lattice energy decreases down a group so does I.E

Covalent bonds

Involve sharing of electrons between atoms in a molecule

In general stronger than hydrogen bonds

Multiple bonds are …

Stronger but shorter than single bonds

If there is a greater bond energy

the greater the attraction between the atoms