SC5 + SC6 Ionic Bonding + Covalent Bonding Flashcards
Define cations
Positive ions formed when atoms lose electrons
Define anions
Negative ions formed when atoms gain electrons
Define dot and cross diagrams
Show the arrangement of electrons in an atom or ion
Define an atom
the smallest piece of an element
Define an ion
charged particles - this can be a single atom or a group of atoms
Ions ending with -ide are…
negative ions containing only one element
Ions ending with -ate are…
negative ions containing oxygen and at least one other element
How do you work out the formula of an ionic compound?
1) Write out the formulas of the ions eg. calcium and nitrate ions Ca(2+) NO3 (-)
2) The overall charge on the formula must be zero, so work out the ratio of Ca:NO3 that gives an overall neutral charge
Therefore Ca(NO3)2
Define an ionic bond
A metal and a non-metal reacting together.
List the properties of ionic compounds
- High mp/bp due to strong attraction between ions
- Dissolve easily in waer
- Giant lattice structure
Why do ionic compounds conduct electricity molten / in aqueous solutions, but not as solids?
In a solid, the ions are fixed so can’t move freely.
In a liquid, the ions are free to move so can carry an electric current
Define a covalent bond
A bond formed when a pair of electrons are shared between two atoms
Examples of covalent bonds
Hydrogen H2, Water H20, Methane CH4, Oxygen O2
List the properties of covalent bonding
- Simple molecular structures
- Weak forces of attraction but strong bonds
- Low mp/bp
- Don’t conduct electricity
