topic 1 - structure and bonding Flashcards
ion
a charge particle
anion
a negative ion
formed through electron gain
what groups form anions
6 and 7
cation
a positive ion
formed through electron loss
what groups readily form cations
1 and 2
how is an ionic bond formed
a metal atom loses electrons to form a cation
a non metal atom gains these electrons to form an anion
the two oppositely charged ions are strongly attracted to one another by ELECTROSTATIC FORCES
ions ending in -ate
negative
contain oxygen and at least one other element
ions ending in -ide
negative
only contain one element (excluding hydroxide)
structure of ionic compounds
regular, giant ionic lattice held together by strong electrostatic forces between oppositely charged ions
properties of ionic compounds
high melting and boiling points
conduct electricity when molten or aqueous
why do ionic compounds have high melting and boiling points
takes a lot of energy to overcome the strong electrostatic attraction
why do ionic compounds conduct electricity when molten or aqueous
when solid, the ions are held in place so can’t conduct electricity
when molten/aqueous, ions are free to move and therefore can carry electric current
covalent bond
a strong bond formed when a pair of electrons is shared between two atoms
covalent bond features
weak intermolecular forces
uses non metal atoms
creates molecules
properties of simple covalent compounds
low melting and boiling points
poor conduction of electricty
why do simple covalent compounds have low melting and boiling point
the intermolecular forces are weak so not much energy is needed to overcome them