1chemical formulae, equations and calculations and ionic bonding Flashcards
rfm =
ram (thing under the element on periodic table)
moles =
mass / rfm
percentage yield =
(actual yield / theoretical yield) x 100
molecular formula
the formula that shows the number and type of each atom in a molecule
empirical formula
the simplest whole number ratio of the atoms of each element present in one molecule or formula unit of the compound
organic molecules often have different
molecular and empirical formulas
the formula of an ionic compound is always
an empirical formula
empirical formula gives
the simplest whole number ratio of atoms of each element in the compound
an ion is
an electrically charged atom or group of atoms formed by the loss or gain of electrons
the loss or gain of electrons takes place to
obtain a full outer shell of electrons
negative ions are called
anions and form when atoms gain electrons- meaning they have more electrons than protons
positive ions are called
cations and form when atoms lose electrons- meaning they have more protons than electrons
all metals lose electrons to
become positively charged ions
all non metals gain electrons
from other atoms to become negatively charged ions
how do deduce the charge of an ion
- Find the number of electrons in the outer electron shell
- Find out if it is easy for the atom to gain electron or to donate electron (in most cases atoms that have fewer than four electrons, donate electrons and atoms that have more than 4 electrons, receive electrons)
atoms that gain electrons become
negatively charged and atoms that donate electrons form positive ions
charge/formula of group 1 metals
1+
charge/formula of group 2 metals
2+
charge/formula of group 3 metals
3+
charge/formula of silver
Ag+
charge/formula of copper (II)
Cu2+
charge/formula of iron (II)
Fe2+
charge/formula of iron (III)
Fe3+
charge/formula of lead
Pb2+
charge/formula of zinc
Zn2+
charge/formula of hydrogen
H+
charge/formula of ammonium
NH+
4
charge/formula of group 5 non metals
3-
charge/formula of group 6 non metals
2-
charge/formula of group 7 non metals
1-
charge/formula of hydroxide
OH-
charge/formula of carbonate
CO 2-
3
charge/formula of nitrate
NO -
3
charge/formula of sulphate
SO 2-
4
charge/formula of chromium (III)
Cr 3+
charge/formula of hydrogen carbonate
HCO -
3
for ionic compounds you have to balance the charge of each part by
multiplying each ion until the sum = 0
ionic bonding
the electrostatic force of attraction between oppositely charged ions
ionic compounds are made up of
charged particles called ions which from a giant lattice structure
ionic substances- mp/bp
ionic substances have high melting and boiling points due to the presence of strong electrostatic forces acting between the oppositely charged ions
ionic compounds at room temp
usually solid and are non-volatile (do not vaporise easily)
ionic compounds can conduct electricity in
molten state or in solution as they have ions that can move and carry charge
why can’t ionic compounds conduct electricity in solids states
as the ions are in fixed positions within the lattice and are unable to move
