Ionic compounds Flashcards
what is an ion?
charged particle formed when an atom loses or gains electrons
what do metal/ non metal atom lose/gain to form ions? and what type?
- metal atoms lose electrons to form positively charged ions (cations)
- non-metal atoms gain electrons to form negatively charged ions (anions)
why are ionic bonds formed?
The oppositely charged ions are strongly attracted to each other, forming ionic bonds.
what can be used to model the transfer of electrons?
a dot and cross diagram
what are ions arranged in?
regular, repeating arrangement called an ionic lattice
why is the lattice formed?
the ions attract each other and form a regular pattern with oppositely charged ions next to each other.
what is the ionic lattice held by?
ionic bonds
in three-dimensional models, what are ionic bonds shown as?
straight lines between ions.
what are ionic bonds (as a force)?
strong electrostatic forces between oppositely charged ions.
what are ionic compounds at room temperature?
solids
what are Melting and boiling?
state changes
what must happen in order to melt or boil an object? and why?
- energy has to be transferred to a substance in order to melt or boil it.
- energy is needed to break the bonds between particles in the substance
what happens to bonds during melting and boiling?
- some bonds are overcome during melting
- all remaining bonds are overcome during boiling
what is the correlation between the melting and boiling point and the energy needed?
The more energy needed, the higher the melting point or boiling point.
why do ionic compounds have high melting and boiling points? (2)
- ionic lattice contains large number of ions,
- lots of energy is needed to overcome these ionic bonds
- so ionic compounds have high melting and boiling points
A substance can conduct electricity if:
it contains charged particles, and
these particles are free to move from place to place
how do ionic compounds conduct electricity? (2)
when molten to form a liquid or dissolved in water to form an aqueous solution.
why do we melt/ dissolve ionic compounds to make them conduct electricity?
This is because both processes make their ions free to move from place to place
why can ionic compounds not conduct electricity when solid?
their ions are held in fixed positions and cannot move.
what are ionic compounds when solid?
insulators
what must a formula for an ionic compound contain? and why?
-same number of positive and negative charges so that the charges are balanced and it is neutral overall.
what are ployatomic ions?
ions formed from groups of atoms
what does it mean when an ionic compound ends in -ide?
-ide if it contains just two elements
what does it mean when an ionic compound ends in -ate?
-ate if it contains three or more elements, one of which is oxygen
