Ionic Compounds Flashcards
Define an ionic bond
electrostatic attraction between oppositely charge ions
What is the difference between an ionic bond and a metallic bond?
both electrostatic attraction
both giant structure with many bonds
Both contain metal ions
BUT
Metallic is the attraction between a metal ions and delocalised electrons
Ionic is the attaction betwen a metal ion and a negative ion (or oppositely charge ions)
Why do ionic compound have high melting points?
- There are many strong ionic bonds in a giant lattice structure
- requires a lot of energy to overcome
Explain what happens in terms of electrons when Na reacts with Cl to form NaCl
Na is from group 1 and loses one electron to become Na+
This electron is transferred to the chlorine atom which gains one electron to become Cl -
Na+ Cl-
Why is an ionic compound soluble in water but not soluble in an organic solvent?
Ionic compounds consist of charged ions and water molecules are polar (have charged ends on the molecule) this forms electrostatic attraction which can pull ionic compounds apart making them dissolve or dissociate
organic solvents do not have polar molecules (or molecules with charged ends) so they cannot attract and pull apart the ions in ionic compounds.
Which compound is ionic?
CH4 H2O MgCl2 NH3 CO2
Ionic compounds are formed when an electron is transferred from one atom to another.
Ionic compound consist of a metal from the left hand side of the periodic table which really wants to give electrons and a non-metal from the right hand side of hte periodic table which really wants to gain electrons
CH4 H2O MgCl2 NH3 CO2
MgCl2 is the ionic compound- formed of a metal and non-metal
Why are ionic compounds brittle?
The positive and negative ions are in layers and are arranged in an alternating pattern. This means that the positive ions are attracted to the negative ions and the whole compound is held together tightly.
If a set of layers are disrupted and slide in one direction, the positive ions are now postioned across from each other and they repel.
This breaks the layers apart - making the compound brittle
Why do ionic compounds conduct electricity when molten or in solution but not when it is in solid form?
When ionic compounds are molten or in solution the charge ions are free to move and carry charge
When ionic compounds are solid, the ions are not free to move and cannot carry charge.
Why do metals and ionic compounds both have high melting points?
They both have many strong bonds in a giant structure
which requires a lot of energy to overcome
Why is the melting point of MgO higher than the melting point of NaCl?
Mg ion has a charge of 2+ and oxygen ion has a charge of 2-
Na ion has a charge of 1+ and chloride ion has a charge of 1-
The ions in MgO have double the charge and therefore have a much greater electrostatic force of attraction
This requires more energy to overcome the ionic bonds in MgO than in NaCl
Why do both metals and molten ionic compounds conduct electricity?
Both have charge particles which are free to move and carry charge
But, metals have negatively charge electrons which can carry charge and molten ionic compound have both postive and negative ions which can carry charge.
Why are metal malleable but ionic compounds are not?
Metals layers can slide but the delocalised electrons which form the metallic bond are not disrupted and they remain between the layers as they slide.
This means the metallic bond is not disrupted and the metal is still held together
Ionic compound layers are held together by the electrostatic attraction of oppositely charge ions. If these alternating ion layers are shifted on atom along, then similarly charge ions are now aligned and they repel and push the layers apart.
Explain in terms of electrons what happens when Mg reacts with O to form MgO
Mg loses 2 electrons to form Mg2+
O gains two electrons from Mg to become O2-
Two electrons are transferred from Mg to O
Explain in terms of electrons how Mg and Cl react to form Magnesium chloride
Mg loses 2 electrons to form Mg2+
Two Cl atoms gain one electron each to form two Cl- ions
Mg2+ 2 [Cl1-]
Explain in terms of electrons how Na and O react to form sodium oxide
Two Na ions lose one electron each to form 2 Na+ ions
One oxygen atom gain these 2 electrons to form O2-
2[Na+] O2-
Na2O
All salts have which type of bonding?
ionic bonding
The electrostatic attraction between oppositely charge ions
What is the formula of sodium chloride?
NaCl
Na is in group 1 - has valency of 1+
Cl is in group 7 - has valency of 1-
What is the formula of sodium oxide?
Na2O
Na is in group 1 - has valency of 1+
O is in group 6 - has valency of 2-
Use cross and drop….
What is the formula of sodium nitride?
Na3N
Na is in group 1 - has valency of 1+
N is in group 5 - has valency of 3-
Use cross and drop….
What is the formula of magnesium nitride?
Mg3N2
Mg is in group 2 - has valency of 2+
N is in group 5 - has valency of 3-
Use cross and drop….
What is the formula of magnesium oxide?
MgO
Mg is in group 2 - has valency of 2+
O is in group 2 - has valency of 2-
Use cross and drop…. anc cancel down to simplest ratio
What is the formula of calcium fluoride?
CaF2
Ca is in group 2 - has valency of 2+
F is in group 7 - has valency of 1-
Use cross and drop….
What is the valency of the hydroxide ion
OH 1-
What is the valency of a carbonate ion
CO3 2-
What is the valency of a nitrate ion?
NO3 1-
What is the valency of a sulfate ion?
SO4 2-
What is the valency of an ammonium ion?
NH4 1+
What is the valency of a zinc ion?
Zn 2+
What is the valency of a silver ion?
Ag 1+
What is the valency of a lead ion?
Pb 2+
What are the two possible iron ions?
Fe 2+ and Fe 3+
What are the two possible copper ions?
Cu 1+ and Cu 2+
What is the valency of a hydrogen ion?
H 1+
Name the complex ion and give its valency
OH
hydroxide ion
OH 1-
Name the complex ion and give its valency
NO3
nitrate ion
NO3 1-
This is the complex ion, SO4. State its name and its valency
sulfate ion
valency is SO4 2-
Name this complex ion and give its valency
NH4
ammonium ion
valency 1+
This is the CO3 complex ion. State its name and valency
Carbonate ion
valency 2-
