El 7 Flashcards
What is ionic bonding?
Ionic bonding is the complete transfer of valence electron(s) between atoms and is a type of chemical bond that generates two oppositely charged ions.
How are ions formed?
When electrons are transferred from from one atom to another atom to gain the nearest noble gas electronic configuration
What do metals form when they lose electrons?
Positive cations, they are therefore smaller than the original atom.
What do non-metals form when they gain electrons?
negative anions, they are therefore larger than the original atom because of the electron repulsion in the outer shell
What is the energy associated with removing the electrons?
First ionisation energy
Why is energy released when a non metal atom becomes a negatively charged anion?
Energy is released as the nucleus pulls in an electron this energy that is released is called electron affinity
What is electron affinity?
Electron affinity is the change in energy of a neutral atom when an electron is added to the atom to form a negative ion (the neutral atoms likelihood of gaining an electron)
What is the general trend of the charge on a metal ion?
Its charge is equal to its group number
What is the general trend of the charge on a non-metal ion?
Its charge is equal to its group number minus 8
How are oppositely charged ions held together?
They are held together by their opposite charges in an electrostatic bond and the oppositely charged ions attract each other strongly (When ions are held together like this, its called ionic bonding)
What is a complex ion?
Complex ions are ions that contain more than one type of atom, the whole ion group carries an electrical charge (the electrical charge is spread across the whole group)
What is the structure of an ionic compound?
Ionic compounds contain oppositely charged ions that are held together in a giant lattice structure.
How does a lattice stay together?
Within the lattice, the ions with different charged attract each other and the ions with the same charge repel each other. The ions arrange themselves to maximise the attractions and minimise the repulsions.
What is the overall attraction in a lattice structure called?
Ionic bonding
What are ionic crystals?
Ionic crystals are giant lattices of ions, a lattice is just a regular structure
What state are ionic substances at room temperature and pressure (typically)
Solids
How is the lattice structure arranged?
The lattice structure consists of repeating positive and negative ions in all 3 dimensions, because of this, ionic compounds often form regularly shaped crystals
When do ionic compounds conduct electricity?
When molten or dissolved in a solution
Do ionic compounds have high or low melting points?
High melting points
Are ionic compounds typically soluble or insoluble?
Soluble
Why do ionic substances only conduct electricity when molten or dissolved - but not when they’re solid?
Ions in a liquid or a solution can move around freely and take their electrical charges with them. Ionic compounds conduct electricity when dissolved in water, because the dissociated ions can carry charge through the solution.
Why do ionic compounds have high melting points?
The ions in a giant lattice are held together by strong electrostatic forces of attractions between each individual ion. A large amount of energy is required to overcome theses forces so their melting points are high.
Why are most ionic compounds soluble?
Ionic compounds dissolve readily in water because water molecules are polar (one end is slightly positive and one end is slightly negative). The ions in the compound also have a small negative or positive charge and therefore, the water molecules can attract the ions and pull the ions away from the lattice. The ions become surrounded by water molecules and spread out evenly throughout the solution, once the ions are separate they behave independently of each other (can undergo separate reactions).
What ionic compounds are insoluble?
Barium, lead and silver sulphates
Silver and lead halides
All metal carbonates
Metal hydroxides except group 1 hydroxides and ammonium hydroxide