Ionic, covalent and metallic structures. * Flashcards
What is an ion?
an atom or group of atoms with an electrical charge
How are ions formed? (4 points)
Key words:
atoms, outer shell, electrons. unequal, charge, metal, non-metal
- atoms with incomplete outer shells either lose or gain electrons
- the atom then has an unequal number of protons and electrons
- this means it has an overall charge
- one atom must be metal, and one must be non-metal
What charge will an atom that loses electrons have?
if it loses electrons, it will have more protons than electrons, giving it a positive charge
What charge will an atom that gains electrons have?
if it gains electrons, it will have more electrons than protons, giving it a negative charge
What charge will an atom that gains electrons have?
if it gains electrons, it will have more electrons than protons, giving it a negative charge
What does the group number show about the atom?
the number of electrons in the outer shell
Do groups 1-3 lose or gain electrons?
lose
Do groups 5-7 lose or gain electrons?
gain
Do metal atoms lose or gain electrons?
What charge will they have?
metal atoms lose electrons
they have a positive charge
Do non-metal atoms lose or gain electrons?
What charge will they have?
non-metal atoms gain electrons
they have a negative charge
What is a compound ion?
an ion made up of a group of atoms
Name five compound ions and give their formulae
- hydroxide = OH -
- sulfate = SO4 2-
- nitrate = NO3 -
- carbonate = CO3 2-
ammonium = NH4 +
What must an ion drawing always have?
- square brackets around the outside
- a + or - outside the brackets
What is an ionic bond?
an ionic bond is the electrostatic force of attraction between oppositely charged electrostatic ions
Ionic compounds:
Fill the gaps:
the formation of an _____ ____ involves the transfer of _________ from the _____ to the ___-_____
the formation of an ionic bond involves the transfer of electrons from the metal to the non-metal
Ionic formulae:
Fill the gaps:
the ratio of _____ to ___-_____ ions is the amount of ________ ____ or ______
some ionic __________ contain __________ ions so ________ are used
the ratio of metal to non-metal ions is the amount of electrons lost or gained
e.g KCl has a 1:1 ratio as its K+ and Cl- so it balances out
e.g. K2O has a 2:1 ratio as its K+ and O2- so 2 K ions are needed to balance the charge
some ionic compounds contain compound ions so brackets are used
e.g. calcium nitrate = Ca(NO3)2 which shows you have 1 Ca2+ and 2 NO3 ions
What is oxidation?
oxidation is losing electrons
What is reduction?
reduction is gaining electrons
Give three properties of ionic compounds
- conducts electricity when molten - the ions are free to move and carry a charge
- high melting and boiling point - giant lattice structure which requires a lot of energy to break
- soluble in water - attracted to the water molecules which carry a small electrostatic charge
What kind of structure do ions have?
ions have a giant ionic lattice structure
the lattice is formed because the ions attract each other and form a regular pattern with oppositely charged ions next to each other
What is covalent bonding?
a shared pair of electrons between 2 atoms
Which type of element can form covalent bonds? (metal/non-metal)
non-metal
How does covalent bonding happen? (4 points)
Key words:
non-metal atoms, pair of electrons, molecule, covalently bonded element, covalently bonded compound
- when two non-metal atoms overlap they share a pair of electrons
- this forms a molecule
- if the atoms are all the same type then it forms a covalently bonded element
- if the atoms are different then it forms a covalently bonded compound
What does the number of electrons on the outer shell show?
how many covalent bonds an element will form
