Bonding Flashcards
What creates the ionic lattice?
The ions attracting oppositely charged ions in all directions
What state are most ionic compounds at room temperature?
-Solid
Why do ionic compounds have high melting points?
-strong electrostatic forces of attraction between ions
Why do ionic lattices with greater charges have greater melting points?
There are stronger forces of attraction between ions
What do most ionic compounds dissolve in?
Polar solvents
How does an ionic compound dissolve in water?
The polar water molecules break down the lattice by isolating the ions
Why are lattices with grater ionic charge generally less soluble?
There is a stronger electrostatic attraction between particles
What is the formula for an ammonium ion?
NH4+
What is the formula for a nitrate ion?
NO3-
What is the formulae for a sulfate ion?
SO42-
What is the formula for a phosphate ion?
PO43-
What is covalent bonding?
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms
How does a covalent bond take place?
The overlap of atomic orbitals (one in each orbital to form a pair)
Why are covalent bonds “localised”?
The bond is purely between atoms
How many single covalent bonds does boron tend to make?
3
Despite it’s outer electrons being n=3, how many covalent bonds can phosphorus make? What is this called?
5 - expansion of the octet
What is another word for a dative bond?
A coordinate bond
What is a dative bond?
When the shared pair of electrons has been supplied by one of the bonding atoms only
What is a dative bond shown by?
——>
What is average bond enthalpy a measurement of?
Covalent bond strength
What does a greater bond enthalpy value indicate?
A stronger covalent bond
Why does H3O have a 1+ charge?
A pair of electrons is provided by the oxygen atom as it pairs with a H+ ion
How are ionic compounds formed?
When 2 oppositely charged ions attract and are held together by electrostatic forces
What are 3 properties of ionic compounds?
1) High MP and BPs
2) Can’t conduct electricity when solid
3) When molten or aqueous can conduct electricity
Why can ionic compounds conduct electricity when molten or aqueous?
The ions are mobile and can move to opposite terminals and carry charge
How are the ions in a lattice isolated by the polar water molecules?
The ions are attracted to slight charges on the polar molecule
Why can a sodium ion form more than one ionic bond even though it only has one outer electron?
Each ions is attracted to all nearby ions
Why do lone pairs repel more strongly than bonded pairs?
They are held closer to the central atom
What is the electron pair repulsion theory used for?
To predict and explain the shapes of molecules
Why do larger ions have a weaker attraction to the oppositely charged ion?
They have a greater ionic radius, so attractive forces have to act over a greater distance.
Why are ionic substances often brittle?
The layers of alternating chargers are distorted when force is applied, so like charges repel, breaking apart the lattice into fragments.
In a covalent bond dot and cross diagram, are the electrons on the lines or inbetween?
Doesn’t matter but should do it in between
Why are shorter covalent bonds stronger ?
Atoms are held closer together so the forces of attraction are greater and require more energy to overcome
Are double and triple bonds shorter than single covalent bonds?
Yes so they are stronger
Why is a dative bond treated as a standard covalent bond once it has formed?
It reacts exactly the same way and has the same properties regarding length and strength
