Periodic Patterns Flashcards
What is covalent radius
Half the distance between nuclei of atoms that are covalently bonded together
As you go down a group, covalent radius…
Increases
Why does covalent radius increase as you go down a group
- number of electron shells increases
- increased shielding
- electrons further away from nucleus
- atom size increases
As you go across a period, covalent radius…
Decreases
Why does covalent radius decrease as you go across a period
- electrons are gradually filling up energy levels
- more protons
- increased nuclear charge
- electrons pulled in closer and tighter
- atom size decreases
What unit is atomic size measured in
Picometers (pm)
1 x 10^-12 m
What is Van der Waals radius
Half the distance between atoms nuclei that aren’t bonded together
What is the first ionisation energy
The energy required to remove 1 mole of electrons from 1 mole of gaseous atoms
What is the general equation for the first ionisation energy
M (g) ——> M+ (g) + e-
What is the second ionisation energy
The energy required to remove a second mole of electrons
What is the general equation for the second ionisation energy
M+ (g) ——> M 2+(g) + e-
What is the third ionisation energy
The energy required to remove a third mole of electrons
What is the general equation for the third ionisation energy
M 2+(g) ——> M 3+(g) + e-
As you go down a group, ionisation energy…
Decreases
Why does ionisation energy decrease as you go down a group
- number of electron shells increases
- atomic size increases
- outer electrons are further away from nucleus
- increased shielding
- less energy required to remove e-
