Bonding (ionic) Flashcards
Define ionic bonding
The electrostatic forces of attraction between oppositely charged ions
What charge ion does group 5, 6 and 7 atoms form?
Group 5 = -3 charge
Group 6 = -2 charge
Group 7 = -1 charge
What charge ion do group 4 and group 0 atoms from?
Group 4 doesn’t have a charge
Group 0 has a charge of 0
How are cations formed? Which elements tend to form cations?
Cations are formed by atoms losing electrons
Elements in groups 1,2 and 3 tend to lose electrons to form cations
What is the general equation for forming cations?
X ~> x ^n+ + xe-
What happens when atoms become ions?
They achieve stable noble gas configuration because the ions have full outer shells
How are anions formed?
What elements tend to form anions?
Anions are formed when atoms gain electrons to form positive ions
Elements in group 5 to 7
What is the general equation for forming anions? (Diatomic)
X2 + 2ne- ~> xn-
What is the valency number?
The valency number is the number on the charge of an ion without the positive or negative charge eg magnesium has a valency of 2
How do you write formulas of ionic compounds using the valency method?
Write the each element and their charges
Use that to get their valency number
Cross the valencies
Write formula
How did you write formulas of ionic compounds using the balancing charges method?
Write each element and their charges
Calculate how many of each you would need to get overall charge of 0
Why are Roman numerals used in the names of some metals?
Give an example
Some metals (usually in the d block) can form various ions so to identify which one it is the Roman numerals are used
For example Cu 2+ ions are Cu (II)
V 4+ ions are V (IV)
What is a simple ion?
Give an example
An ion that is made from one element / atom eg Na
What is a polyatomic or complex ion?
Give an example
An ion that contains more than one type of atom, for example NH4+
What are the 7 common polyatomic ions and their formulas?
Ammonium NH4+
Nitrate N03-
Hydroxide OH-
Hydrogensulfate HSO4-
Sulfate S042-
Carbonate CO32-
Phosphate PO4 3-
What is the rule for polyatomic ions and writing formulas?
If a polyatomic ion has a valency greater than 1 after swapping them then you must sue brackets
Define an acid
A proton donor (H+)
Why is aqueous HCl and acid but solid HCl isn’t?
Aqueous HCl is able to donate H+ ions because the water separates the H+ and Cl-
Solid HCl has particles held in a diced position so it cannnot donate a proton
What does aqueous mean?
Dissolved in water
What are the 5 common acids and their formulas?
Hydrochloric acid HCl
Sulfuric acid H2SO4
Nitric acid HNO3
Phosphoric acid H3PO4
Carbonic acid H2CO3
What is a lattice?
A regular, repeated three dimensional arrangement of Jon’s / molecules or atoms in a solid
What is a crystal structure?
A solid material whose constituents I.e molecules, atoms or ions are arranged in a highly ordered structure, forming a lattice that extends in all directions
What are non crystalline structures called?
Amorphous
How do you draw giant ionic lattices?
Draw a cube
Place an ion in the middle of each line
Place the opposite ion of the middle one in each corner
Place the same ion as the corner one on each side of the cube
What is the melting and boiling point like in ionic compounds?
They have high melting and boiling points because there are strong electrostatic forces of attraction between the oppositely charged ions which require a lot of energy to break
What are the 2 conditions for conductivity?
Delocalised ions
Delocalised electrons
What is conductivity like in solid ionic compounds and why?
Solid ionic compound - don’t conduct electricity because the ions are held in the lattice structure so can’t move so can’t carry a charge
What is conductivity like in molten ionic compounds and why?
They can conduct electricity as the ions are free to move so can carry a charge
What is conductivity like in aqueous ionic compounds and why?
They can conduct electricity because the ions are separated by the water molecules so they are free to move so carry charge
What makes water a polar molecule?
There is covalent bonding so both oxygen and hydrogen attempt to pull the electrons towards themselves. Oxygen has a higher electro negativity so it can pull the electrons closer which leaves it with a slight negative charge and hydrogen has a slight positive charge
Why do atoms try to pull electrons towards themselves in covalent bonds?
To achieve greater stability
How does water pull apart ions in solutions?
The delta plus and delta minus charge on hydrogen and oxygen can pull the ions apart by attracting them oppositely charged ones
What ions are soluble and when? (4)
All NO3- compounds
All NH4+ , Na+ and K+ compounds
All Cl- , Br- and I- compounds
All SO42- compounds except with Ca2+ and strontium (Sr2+) and lead (Pb2+)
What ions are insolubles and when? (2)
All CO32- (carbonate) compounds except with NH4+ ammonium , Na+ sodium and K+ potassium
All OH- (hydroxide) compounds except with NH4+ ammonium, Na+ sodium and K+ potassium
What are 2 things that affect the strength of ionic bonds?
The ionic charge
The size of an ion
How does the size of an ion change as you go down groups and accords periods?
Down = increase
Across = decrease
