Chemical Bonding Flashcards
Valency and ionisation energy rule
In order to remove electrons that are closer to the nucleus than the valence electrons, a lot more energy is needed, so if there is a big jump in IE in between the 3rd and 4th for example, it means the element has 3 valence electrons and is in group 3
Types of chemical bonding (3)
Ionic
Metallic
Covalent (pure and polar)
Electronegativity
The power of an atom to attract electrons to itself
Pure covalent bond electronegativity value
0 - 0.4
Polar covalent bond electronegativity value
0.5-1.9
Ionic bond electronegativity value
> 1.9
Factors that affect electronegativity (2)
Across the period
Down the group
How moving across the group affects electronegativity
As you move across the period, there in an increase in the number of protons which results in a greater nuclear charge and a larger electronegativity value
How moving down the group affects electronegativity
As we move down the group, the atomic radius increases along with the shielding effect resulting in a lower electronegativity value
Ionic bonding
The electrostatic attraction between oppositely charges ions (positively charged cations and negatively charged anions
Ionic bond properties (4)
High MP+BP - strong electrostatic forces between oppositely charged ions
Conducts if molten/aqueous - If solid the ions are in a fixed crystal lattice = can’t carry charge
Brittle
Soluble in polar solvents
Metallic bonding
Electrostatic attraction between positive cations and delocalised electrons
Properties of metallic bonds (3)
Malleable and ductile (due to non-directional bonds)
High conductivity (due to delocalised electrons)
High melting and boiling point(strong electrostatic force between cations and anions(the high the P number the more))
Covalent bonding
The electrostatic attraction between the nuclei of 2 atoms and shared pair of electrons
Polar covalent
When there is an unequal distribution of charge
Single bond (3)
(Single sigma (σ) bond)
Overlap of s-orbitals
Overlap of s and p-orbitals
Head to toe overlap of p-orbitals
Pi bond
Forms from the sideways overlap of p-orbitals
Double bond
1 σ (sigma) bond and 1 π (pi) bond
CAN ONLY FORM IF YOU HAVE A P VALENCE ELECTRON