Summer Assessments 2 Flashcards
What are ions
charged particles
Why do atoms lose/ gain electrons
to form ions as they are trying to get a full outer shell as atoms with a full outer shell are very stable
What are negative ions and when do they form
anions
-form when atoms gain electrons
What are positive ions and when do they form
cations
-form when atoms lose electrons
What are the charges for metals in Groups 1, 2, 3
-lose electrons to form positive ions so:
Group 1 elements form 1+ ions
Group 2 elements form 2+ ions
Group 3 elements form 3+ ions
What are the charges for non-metals in Groups 5, 6, 7
-non-metals gain electrons to form negative ions so:
Group 5 elements form 3- ions
Group 6 elements form 2- ions
Group 7 elements form 1- ions
Name 6 ions and there charges that go against the normal
Ag+ Cu2+ Fe2+ Fe3+ Pb2+ Zn2+
Name 6 elements and there charges that go against the normal idea
Hydrogen (H+), hydroxide (OH–), ammonium (NH4+), carbonate (CO32–),
nitrate (NO3-)
sulfate (SO42–).
What does ionic bonding involve
a metal and a non-metal
Describe ionic bonding in terms of electrostatic attractions
Ionic bonding is the electrostatic attraction between oppositely charged ions
Why do compounds with giant ionic lattices have high melting and boiling
points
ions are held together in a closely packed 3D lattice arrangement by the attraction between oppositely charged ions
- the electrostatic attraction between oppositely charged ions is very strong
- as a result of this a lot of energy is needed to overcome the strong attraction
- hence why ionic compounds have high melting and boiling point
When can ionic compounds conduct electricity
- conduct
electricity when molten and in aqueous solution
-can’t conduct electricity when solid
Name the 3 physical properties of ionic compounds
- high melting point
- high boiling point
- can conduct electricity when molten or when dissolved in water
What do compounds with ionic bonding always have
giant ionic structure
What diagram is used to show the transfer of electrons in ionic bondidng
A dot and cross diagram
Describe covalent bonding in terms of electrostatic attractions
Covalent bonding is the electrostatic attraction between negatively charged shared electrons
What is a covalent bond
A shared pair of electrons
Why are substances with a simple molecular structure gases or liquids, or
solids with low melting and boiling points
- atoms within a molecule are held together by very strong covalent bonds
- the molecular forces of attraction between the molecules are very weak
- therefore the melting and boiling point for simple molecular substances are very low as the molecules are easily separated
explain why the melting and boiling points of substances with simple molecular
structures increase, in general, with increasing relative molecular mass
- intermolecular forces are stronger between molecules with high relative molecular mass (Mr) than between smaller molecules
- as there are more points along larger molecules for intermolecular forces to act between them
- so more energy is needed to break the forces
- due to increasing strength of the forces, melting and boiling pints of simple molecular substances increase as the relative molecular mass increases
How are giant covalent structures bonded to each other
-strong covalent bonds
explain why substances with giant covalent structures are solids with high melting and
boiling points
- giant covalent structures bonded to each other by strong covalent bonds
- there are lots of these bonds so it takes a lot of energy to break them
- hence why giant covalent structures are solids with high melting and boiling points
Do Giant Covalent Structures conduct electricity
No- not even when molten
Why does diamond have a high melting and boiling point
- diamond is made up of a network of carbon atoms that each form 4 covalent bonds
- the strong covalent bonds take lots of energy to break, so diamond has a high melting point
Why is diamond hard
as the strong covalent bonds hold the electrons in a very rigid lattice structure
