Davide Della Libera, Nadja Ganter, Andrea
Susnik and Kelsey Lee
Monovalent Compounds
O Monovalent Compounds are compounds
that have only one ionic charge, which
means they have one valence electron to
form a ionic bond with some other elements
or compounds. We can also recognise them
because in the periodic table, they are those
which have only a + or – in their top right.
For example:
Bisulfate (hydrogen sulfate) HSO4-
Multivalent Compounds are ionic
compound metals with different
numbers of electrons, having more
than one valence. They are located
in the large middle section of the
periodic table (demonstrated to the
bottom left). Because they are
multivalent, they can be seen with
up to 3 possible ionic charges that
are positive, because they are
metals.
Ex.
Fe2+
Fe3+
O Since a multivalent compound can form more than one stable icon, to
determine whether a compound is multivalent or not we must look at
the periodic table to see if the metal has more than one combining
capacity.
O You can also usually determine the combining capacity of the metal by
looking at the formula if the compound by looking at the formula of the
compound: by un-criss crossing the value (looking at the other
element’s value)
O When writing out a multivalent compound, clarify it’s capacity by it
placing in brackets, in roman numerals.
ex. Nickel (III), Manganese (IV).
Polyatomic compounds
O Polyatomic ions comprised of more than one
atom, which share the electrons.
O Examples for polyatomic ions:
O Positive ions: Ammonium NH4+
O Negative ions: hydroxide OH-
From Formula to Name
O Write positive ions name either metal or
ammonium
O Check if metal is multivalent ion, if so
indicate multivalent ions charge in roman
numerals
O Indentify negative ion and name it
O Ex: Cr3 (Po4) 2
O chromate
O Chromate (||)
O Chromate (||) phosphate
From name to formula
O Identify each ion and its charge
O Criss Cross charges
O Put Symbole together and get rid of charge
values. For Polyatomic ions, use brackets
around the ion
O Example:
O Chromium (|||) (Cr3+) Sulphate (SO4-2)
O Cr3+
SO42O Cr2 (SO4) 3
Hydrates
O A solid compound that is surrounded by
water molecules.
O Copper sulfate pentahydrate
How to name it!?
O Steps to naming Hydrates
O Name the compound as you would normally
do so.
O After the compound name, place the
corresponding prefix(# of water molecules)in
front of the word hydrate.
Prefixes
O Ex.
O FeSO4 5H2O= Iron(II) sulphate pentahydrate
O NiSO4 7H2O= Nickel sulphate heptahydrate
O Co3(PO4)2 8H2O= Cobalt(II) phosphate
octahydrate