SC5 Flashcards
(17 cards)
What are bonds?
Forces of attraction that hold atoms together to form elements or compounds.
Why are chemical bonds formed?
Atoms of other elements have incomplete outer shells of electrons and so are unstable so they will bond with other elements to become stable.
What is an ion?
An atom that has an electrical charge, either positive or negative.
What happens when an element gains or loses electrons?
It will have an unequal number of protons and electrons so have an overall charge.
What do we call a positive ion?
Cation.
What do we call a negative ion?
Anion.
What type of ions do metal atoms form?
Metal atoms can lose electrons from their outer shells to form cations.
What type of ions do non-metal atoms form?
Non-metal atoms can gain electrons from their outer shells to form anions.
What does the name of an anion end with?
-ide (e.g. chloride)
What is an ionic bond?
The electrostatic force of attraction between oppositely-charged ions.
What is a lattice structure?
The regular repeating arrangement of ions formed due to their strong ionic bonds.
What do ionic compounds often form due to their regular lattice structure when solid?
Crystals.
What are all the polyatomic ions and their ion formulae?
Ammonium: NH₄⁺
Nitrate: NO₃⁻
Hydroxide: OH⁻
Carbonate: CO₃²⁻
Sulfate: SO₄²⁻
Sulfite: SO₃²⁻
Phosphate: PO₄²⁻
What are the properties of ionic compounds?
- Solids at room temperature
- High melting and boiling points
- Conduct electricity only when molten/dissolved in a solution (not solid)
Why do ionic compounds have high melting and boiling points?
Ionic bonds are very strong so lots of heat energy is required to break these bonds to separate the ions.
Why can ionic compounds conduct electricity only when molten?
As solids, ionic compounds cannot conduct electricity because their ions are bonded strongly together in the lattice and cannot move and carry charge.
When molten or dissolved in water, ions can break free of the lattice and are able to move. The ions are charged particles so can carry an electric current.
What is electrolysis?
The splitting of a compound to its elements by passing electricity through it.
