Bonding Flashcards
What is ionic bonding
Strong electrostatic forces of attraction between oppositely charged ions held in a lattice
Between MgO and NaCl which one is stronger/has a higher melting point
MgO is stronger/has a higher melting point than NaCl because when the ions are smaller and or have higher charges they have higher melting points and are stronger.
The ions involved in MgO are Mg2+ and O2+ where as in NaCl it is Na+ and Cl-
What effect does going down a group have on ionic radii
It increases because the ions have more shells of electrons
Why are positive ions smaller than negative ions
Positive ions are smaller because it has one less shell of electrons and the ratio of protons to electrons has increased so there is a greater net force on remaining electrons holding them more closely
Why do ionically bonded substances have high melting and boilling points
Requires alot of energy to break the strong electrostatic forces of attraction between opposites charged ions
Do ionic compounds conduct electricity? Why?
Yes, When molten/in solution as the ions are free to move and carry charge through the strcture
What is molecular covalent bonding
A shared pair of electrons that has Weak van der waals forces of attraction between molecules
Can molecular covalent molecules conduct electricity? why?
No- all electrons used in bonding and aren’t free to move
Do molecular covalent substances have a high/low melting and boiling point? why?
Low- Weak van der Waals forces of attraction between molecules that don’t take much energy to overcome
Why do macromolecular covalent bonds have high MP and BP
Requires lots of energy to overcome the many strong covalent bonds
Why do metallic compounds have high MP and BP
Strong forces of attraction between metal ions and negatively charged sea of delocalised electrons
Do macromolecular covalent bonds conduct electricity
Most don’t as all electrons are used in bonding
Why do metallic compounds conduct electricity
The delocalised electrons move throughout the metal and to carry charge
Define electronegativity
The ability of an atom to attract the pair of electrons in a covalent bond to itself
Examples of molecular covalent substances
Iodine
Ice
CO2
Water
Methane