Ionisation energy

What is the definition of first ionisation energy?

Energy required to remove one electron from each atom in one mole of gaseous atoms of an element to form one mole of gaseous 1+ ions

What is the trend in first ionisation energies down a group?

Decreases. Atomic radius increases, electron shielding increases, nuclear attraction decreases

What is the trend across a period?

Increases. Nuclear charge increases, similar shielding, nuclear attraction increases, atomic radius decreases

Why does ionisation energy fall from beryllium to boron although they are in the same period?

2p subshell starts to fill, it has a higher energy and there is only one electron to remove, which is easier to remove than the 2s electrons in beryllium

Why doe ionisation energy fall from nitrogen to oxygen?

Highest energy electrons are in a 2p subshell. In oxygen, the paired electrons in one of the 2p orbitals repel one another, making it easier to remove an electron from an O than a N atom

Why does boiling point increase down group 7?

More electrons, stronger London forces, more energy required to break intermolecular forces, boiling point increases

Why does reactivity decrease down group 7?

Atomic radius increases, electron shielding increases, less nuclear

How does increasing ionic size affect lattice enthalpy of group 1 chlorides?

Ionic radius increases, attraction between ions decreases, lattice enthalpy is less negative, melting point decreases

How does increasing ionic charge affect lattice enthalpy?

Ionic charge increases, attraction between ions decreases, lattice enthalpy becomes more negative, melting point increases

Describe the effects of ionic charge and size across period 3

Increasing charge gives more attraction, decreasing size gives more attraction for positive ions. Increasing charge gives more attraction, increasing size gives less attraction for negative ions

How is hydration enthalpy affected by ionic size down group 1?

Ionic radius increases, attraction between ions and water molecules decreases, hydration energy less negative

How does ionic charge affect hydration enthalpy?

Ionic charge increases, attraction with water molecules decreases increases, hydration energy becomes more negative

Why is the second ionisation energy greater than the first (metals)?

2nd electron removed from a cation, greater nuclear attraction