2.2.2- Bonding And Structure Flashcards
What is an ionic bond?
The electrostatic force of attraction between oppositely charged ions formed by electron transfer
What properties do ionic structures have?
-high melting points due to strong electrostatic forces
-conduct electricity when molten or dissolved as ions are mobile
-usually soluble
-brittle
When is ionic bonding strongest?
When ions are smaller and/or have different charges
What is a metallic bond?
Attractions between positive metal ions and delocalised electrons
What are the properties of metallic structures?
-high mp due to strong electrostatic attraction
-conduct electricity
What is a covalent bond?
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
What properties do covalently bonded molecules have?
-low mp due to weak IMFs
-don’t conduct electricity
What covalent bonds are the strongest?
Shorter bonds as the atoms are held closer together
What bonds are shortest?
Double and triple bonds
What is average bond enthalpy?
A measurement of covalent bond strength
What is a dative covalent bond?
Formed when both of the electrons in the shared pair come from one of the bonding atoms
How is a dative covalent bond indicated?
By an arrow from the lone electron paid
What is the Valence Shell Electron Pair Repulsion Theory (VSEPR)?
Simple covalent molecules have a 3D shape due to repulsion
How do electrons repel eachother?
Equally
What does a solid line indicate?
A bond that is in the plane of the paper
What does a wedged line indicate?
A bond that comes out of the plane of the paper
What does a dotted line indicate?
A bond that goes into the plane of the paper
How do lone pairs repel?
They repel more than bonding atoms, reducing the bonding angle by 2.5° per lone pair
How many bonding and lone pairs does a linear shape have?
2 bonding, 0 lone
What bond angle does a linear shape have?
180°