LT#4&5: Types of Bonds Flashcards
Why do chemical bonds form?
Atoms create chemical bonds to achieve more favourable lower energies compared to them being independent
Define Chemical Bond
Intramolecular electrostatic attractions inside of compounds that hold atoms together in molecules
How does creating a bond release energy?
Forces particles to slow down making them lose kinetic energy.
Define Ionic Bond
Force of attraction between a cation and anion due to full opposite charges
EN difference above 1.7
How are ionic bonds formed?
- The metal loses electrons which require an input of ionization energy.
- The non-metal gains electrons which releases electron affinity energy.
- Atoms form ionic bonds in three dimensions which packs them into cube like crystals (known as lattices)
How does forming an ionic bond release energy?
Because they are being held in position in all directions, the ions drastically slow down which releases energy (called lattice energy.)
Define Covalent Bond
Sharing a pair of electrons between two atoms
How are covalent bonds formed?
- Atoms are brought close enough together to overlap 2 partially filled orbitals. This creates a region where you will find electrons more than 95% of the time.
- The 2 nuclei and 2 electrons involved move to positions where their attractive and repulsive forces balance (called optimal particle separation).
How does forming a covalent bond release energy?
Because optimal particle seperation restricts the movement of the electrons, they slow down and release energy (called bond energy).
Define Non-polar Covalent Bond
Relatively equal sharing of electrons between 2 atoms.
EN difference of 0 to 0.5).
No charges.
Define Polar Covalent Bond
Unequal sharing of electrons between 2 atoms.
EN difference of 0.5 to 1.7
Partial charges.
Define Metallic Bond
The attractive force between the oppositely charged cations and free electrons in a metallic crystal.
How are metallic bonds formed?
Metal atoms dump their valence electrons into the empty spaces in the crystal forming a free electron sea.
How does forming metallic bonds release energy?
Because metal cations are held into position by the electron sea, they are forced to slow down and release energy.
