Unit 1 Peridocity Flashcards
What are the 7 diatomic molecules
H2, N2, O2, F2, Cl2, BR2 & I2
What is Covalent Radius
Measure of the size of an atom that is equal to 1/2 the distance between the centres of 2 covalently joined atoms
What happens to covalent radius down a group
Covalent radius Increases
Energy levels increase (Nuclear charge)
Electrons Shielding increase
What happens to covalent radius across a period
Decreases
Nuclear charge increases
Electrons in outer shells are more strongly attracted to the nucleus
What is ionisation energy
Amount of energy required to remove one mole of electrons from one mole of free gaseous atoms
First ionisation
X(g) ⟶ X+(g) + e−
Second Ionisation
Mg+(g) ⟶ Mg2+(g) + e−
What happens to ionisation energy down a group
Decreases
Increased shielding
Covalent radius increases
Electrons further away from nucleus
What happens to ionisation energy across a period
Increases
Nuclear charge increases
Electrons in outer shell are more strongly attracted to the nucleus
Compare 2nd and 3rd Ionisation Energy
3rd electron is being removed from a shell closer to the nucleus
3rd electron is less shielded from the nucleus so more energy is needed to remove it
What is electronegativity
The measurement of the attraction an atoms has for electrons in a bond
What happens to EN down a group
Decreases
Attraction of the nucleus for the shared e decreases
Increased Shielding
What happens to EN across a period
Increases
Nuclear charge increases
Attraction for shared e increases
What happens to ionic radius down a group
Ionic radius increases
More electron shells
What happens to ionic radius across a period
Decreases
Increased nuclear charge
