1.3 - Bonding Flashcards
What is ionic bonding?
Strong, electrostatic forces of attraction between oppositely charged ions held in a lattice
Give an example of an ionically bonded substance
NaCl
How high are ionically bonded substances, boiling point and melting points? why?
High – takes a lot of energy to break strong, electrostatic forces of attraction between oppositely charged ions
Do ionic compounds conduct electricity? why?
Yes, when molten/in solution is the ions are free to move and carry charge
What is simple molecular covalent bonding?
Strong covalent bonds between atoms week VanderWaal forces of attraction between molecules
Are there any loan electrons in simple covalent bonding?
No, all involved in bonding
Can simple molecular covalent molecules conduct electricity?
No, all electrons used in bonding and aren’t free to move
Do you simple molecular substances have high/low, melting points, or boiling points?
No – week, VanderWaal forces of attraction between molecules that don’t take much energy to overcome
Describe, macromolecular, covalent bonding
Lattice of many atoms held together by strong covalent bonds
Do substances with macromolecular covalent bonds have high/low, melting point and boiling points?
High, as it takes a lot of energy to overcome many strong covalent bonds
Do you substances with macromolecular, covalent bonds, conduct, electricity?
Most don’t is all electrons are used in bonding 
Describe the structure of diamond
3-D. Tetrahedral structure of C atoms with each C atom bonded to 4 others.
Describe the structure of graphite
Similar to diamond macromolecular covalent, but each see atom is only bonded to 3 others, so it is in layers.
Wake VanderWaal forces of attraction between layers mean, they can slide over each other – soft, slippery
One electron from each carbon is delocalised and can carry charge – conducts, electricity
Describe metallic bonding
Lattice of positive metal ions strongly attracted to receive delocalised electrons. Latest can slide over each other - malleable.
Do metallic compounds have high/low boiling point than melting points?
High – a strong forces of attraction between positive metal ions and negatively charged, see if delocalised electrons
Do metallic compounds conduct, electricity?
Yes, as delocalised electrons can move throughout the metal to carry charge
How does the strength of metallic bonds change cross the periodic table?
It increases high, melting and boiling points, stronger higher charges on metal ions
More delocalised electrons per ion
Stronger forces of attraction between them
Define electronegativity
The ability of an atom to attract a pair of electrons in a covalent bond
What affects electronegativity?
Nuclear charge
Atomic radius
Electron shielding
What are the four most electronegative elements?
Fluorine
Oxygen
nitrogen
Chlorine
How do you get a nonpolar bond?
Both bonding elements have the same electronegativities
When do you get a polar bond?
Bonding atoms have different electronegativities
What is the strongest type of intermolecular force?
Hydrogen bonding
What is the weakest type of intermolecular force?
Vander Waals
Describe VanderWaals, forces of attraction
Temporary dipoles created by the random movement of electrons
Induced dipole in neighbouring molecules
Temporary induced dipole, dipole attraction, a.k.a. Vandivers force of attraction
Are VanderWaal forces stronger in smaller or larger molecules?
Larger – more electrons
Describe permanent, dipole-dipole attraction
Some molecules with polar bonds have permanent dipoles
Forces of attraction between those dipoles and those of neighbouring molecules
Why is ice less dense than liquid water?
In liquid water, hydrogen bonds, constantly breaking reform as molecules move around
In ice, the hydrogen bonds hold the molecules in fixed positions. This makes them slightly further apart than liquid water.
What is a dative covalent bond?
Formed when an electron deficient atom, except the lone pair of electrons from an atom with a lone pair of electrons
What does the shape of molecules depend on?
Number of electrons in the valance shell of the central atom
Number of these electrons which are in bonded a lone pairs
What does electron pair repulsion theory state?
That electron pairs will take up positions as far away from each other as possible to minimise the opposing forces between them
2 bonded pairs, 0 lone pairs
Linear
180°
3 BP, 0LP
Trigonal planar
120°
4BP, 0LP
Tetrahedral
109.5°
5BP, 0LP
Trigonal bipyramidal
90° and 120°
6BP, 0LP
Octahedral
90°
