Bonding Flashcards
What do ionic bonds form between
A metal and a non-metal
What is the attraction between ions called
Electrostatic attraction between the opposite charges of ions in a lattice
What is the formula and charge of a sulphate ion
SO4 2-
What is the formula and charge of a hydroxide ion
OH 1-
What is the formula and charge of a nitrate ion
NO3 1-
What is the formula and charge of a carbonate ion
CO3 2-
What is the formula and charge of a ammonium ion
NH4 1+
Properties of ionic compounds
Solid at room temperature
Giant structures
High melting points
Conduct electricity when molten / dissolved
What does a covalent bond contain
A shared pair of electrons
What is another name for a dative bond
A coordinate bond
What is a dative bond
Contains a shared pair of electrons with both electrons supplied by 1 atom
How are dative bonds represented
An arrow
Why do metals conduct electricity
They have delocalised electrons
What does the strength of a metallic bond depend on
Number of delocalised electrons
Size of the ions
What are the 4 types of crystal structure
Molecular
Macromolecular
Ionic
Metallic
What is the structure of diamond
Consists of pure carbon
4 covalent bonds
Bond angles of 109.5
What is the structure of graphite
Consist of pure carbon
Has 3 strong covalent bonds and VDW’s
120 bond angles
Has delocalised electrons so can conduct electricity
Why do metals have high boiling points
They have giant structures. Large amounts of energy are needed to overcome the metallic bonds
What are bonding pairs of electrons
2 electrons shared between atoms
What are lone pairs of electrons
A pair of valence electrons (electrons on the outer shell) that are not shared with another atom
Why do pairs of electrons position themselves as far from each other
To minimise repulsion
What is the order of repulsion strength from highest to lowest
Lone pair-lone pair
Lone pair-bond pair
Bond pair-bond pair
How does a lone pair of electrons effect bond angles
A lone pair will push bonding pairs together
What is a molecules shape with 2 bonding electron pairs and what are the bond angles
Linear
180
What is a molecules shape with 3 bonding electron pairs and what are the bond angles
Trigonal planar
120
What is a molecules shape with 4 bonding electron pairs and what are the bond angles
Tetrahedral
109.5
What is a molecules shape with 5 bonding electron pairs and what are the bond angles
Trigonal bipyramidal
120
90
What is a molecules shape with 6 bonding electron pairs and what are the bond angles
Octahedral
90
What is a molecules shape with 3 bonding electron pairs and 1 lone pair. What are the bond angles
Pyramidal
107
What is a molecules shape with 2 bonding electron pairs and 1 lone pair. What are the bond angles
V-shaped
117.5
What is a molecules shape with 4 bonding electron pairs and 2 lone pair. What are the bond angles
Square planar
90
How do you work out number of unbonded electron pairs
Group number - (Number of atoms bonded + charge)
/2
What is electronegativity
The power of an atom to attract a bonding pair of electrons towards itself in a covalent bond
What does electronegativity depend on
Nuclear charge (number of protons in the nucleus)
Distance between nucleus and outer shell
The shielding of the nuclear charge
How does the symmetry of a covalent bond between 2 atoms with different electronegativities change
The bond would be drawn towards the more electronegative atom
What does an unsymmetrical covalent bond cause
A polar bond which can lead to a permanent dipole being formed
What are the 3 types of intermolecular force
VDW forces
Dipole-dipole forces
Hydrogen bonding
What do VDW forces act between
All atoms and molecules
What do dipole-dipole forces act between
Act between molecules with polar bonds
What do Hydrogen bonds form between
Only between h and fluorine, oxygen or nitrogen (FON)
How do VDW forces form
At any one time in a covalent bond, some electrons may happen to be closer to one atom. This will induce a temporary dipole. This then affects neighbouring atoms so they are attracted to each other for a short space of time
What is the order of strength of intermolecular forces
Hydrogen bonding
Dipole dipole bonding
VDW’s
Why are hydrogen bonds important in ice
When water freezes, all H bonds fix the molecules in a stable position. These molecules are further away from each other than liquid water do ice is less dense. This allows fish to survive etc
Give an example of a bond with multiple shared pair of electrons
N≡N
How are metals bonded
Metallic bonding involves attraction between delocalised electrons and positive ions arranged in a lattice
What type of structure is ice
Ice is a molecular crystal that is connected by hydrogen bonds
What type of crystal is iodine
Molecular covalent crystal
What type of crystal is sodium chloride?
An ionic salt
Crystal lattice
What type of crystal is magnesium?
Giant metallic lattice
