ATOMS & MOLECULES
STRUCTURE OF ATOMS
Referring to the periodic table, fill in the table below.
Element
Carbon
Hydrogen
Nitrogen
Oxygen
Symbol
Atomic #
Neutrons
Electrons
C
6
6
6
Na
Mg
15
17
Potassium
Ca
IONIC BONDS
Referring to the periodic table, determine the number of protons and electrons for the following
atoms, ions, and molecules. (Plus signs (+) represent how many electrons have been lost and
minus signs (-) indicate the number of electrons gained.)
a. Protons in a sodium atom (Na) ______________. Electrons in a sodium atom (Na) _______________.
b. Protons in a sodium ion (Na+) _______________. Electrons in a sodium ion (Na+) ________________.
c. Protons in a chlorine atom (Cl) _______________. Electrons in a chlorine atom (Cl) _______________.
d. Protons in a chlorine ion (Cl-) ________________. Electrons in a chlorine ion (Cl-) ________________.
e. Protons in sodium chloride molecule (NaCl) ____. Electrons in a sodium chloride molecule (NaCl) ____.
f.
Protons in a calcium atom (Ca) ______________. Electrons in a calcium atom (Ca) ______________.
g. Protons in a calcium ion (Ca++) ______________. Electrons in a calcium ion (Ca++) _______________.
h. Protons in a oxygen atom (O) _______________. Electrons in a oxygen atom (O) ________________.
i.
Protons in a oxygen ion (O--) ________________. Electrons in a oxygen ion (O--) _________________.
j.
Protons in a calcium oxide molecule (CaO) _____. Electrons in a calcium oxide molecule (CaO) _____.
IONIC AND COVALENT BONDS
Draw the predicted bonds (if any) for the following combinations of atoms. Indicate covalent bonds
by drawing a line between atoms and ionic bonds by giving the charge of each atom.
a. One Mg atom and two Cl atoms.
b. Two N atoms.
c. Two O atoms.
d. Two H atoms and one O atom.
e. Two F atoms and one Ca atom.
f.
One K atom and one Br atom.
g. Two H atoms, one C atom, and one O atom.
h. Two H atoms and one S atom.
i.
One Li atom and one Cl atom.
j.
Two He atoms.
COVALENT BONDS
Procedure:
1. (1) Bond the carbon atoms together in a ring or chain; (2) Next, add the nitrogen atoms if they
are called for; (3) Then add oxygen atoms, if any; (4) Finally, count the number of electrons in the
whole molecule that are still available for bonding. If this number is equal to the number of
hydrogen atoms, simply add one hydrogen to each bondable point. If there are too few
hydrogens to complete available bonds, find two free bondable electrons on adjacent atoms and
have them form a second bond between themselves (a double bond). Remember, carbon can
form 4 bonds, nitrogen 3 bonds, oxygen 2 bonds, and hydrogen 1 bond.
a. Methane (one carbon atom and four hydrogen atoms): CH4
b. Ammonia (one nitrogen atom and three hydrogen atoms): NH3
c. Water (one oxygen atom and two hydrogen atoms): H2O
d. Ethane (two carbon atoms and six hydrogen atoms): C2H6
e. Ethene (two carbon atoms and four hydrogen atoms): C2H4
f. Ethanol (two carbon atoms, one oxygen atom, and six hydrogen atoms): C 2H5OH
g. Aldehyde (one carbon atom, one oxygen atom, and two hydrogen atoms): CH 2O
h. Organic acid (three carbon atoms, two oxygen atoms, and four hydrogen atoms): C 2H3COOH