Copyright © Glencoe/McGraw-Hill, a division of The McGraw-Hill Companies, Inc.
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
63
Ionic Compounds and Metals
Ionic Compounds and Metals
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
7
7.1 Forming Chemical Bonds
The force that holds two atoms together is called a chemical bond.
Chemical bonds form because of attractions between oppositely
charged atoms, called ions, or between electrons and nuclei. The
outermost, or valence, electrons of atoms are the ones mainly
involved in the formation of bonds. The elements within a group
of the periodic table typically have the same number of valence
electrons.
Elements tend to react so as to achieve the stable electron configuration of a noble gas, typically an octet of electrons. A cation, or
positive ion, is formed when an atom loses one or more electrons.
An anion, or negative ion, is formed when an atom gains one or
more electrons. The periodic table is useful in predicting the charges
of ions typically formed by various atoms.
Example Problem 7-1
Determining Charges of Ions
Calcium (Ca, atomic number 20) is an element in group 2 of the
periodic table. Write the electron configuration for a neutral atom of
calcium. Tell how many electrons this atom readily tends to gain or
lose to form an ion. Predict the charge on the ion, write its formula,
and tell whether it is a cation or an anion. Finally, write the electron
configuration of this ion.
A neutral atom of element 20 would have 20 electrons, giving
it the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 . To achieve the
stable electron configuration of a noble gas, the atom would tend
to lose its two valence electrons, producing a cation with a charge
of 2ϩ and the formula Ca 2ϩ . The configuration of this ion would
be 1s 2 2s 2 2p 6 3s 2 3p 6 .
Solving Problems: A Chemistry Handbook
Chemistry: Matter and Change
63
Ionic Compounds and Metals
Ionic Compounds and Metals
SOLVING PROBLEMS:
A CHEMISTRY HANDBOOK
CHAPTER
7
7.1 Forming Chemical Bonds
The force that holds two atoms together is called a chemical bond.
Chemical bonds form because of attractions between oppositely
charged atoms, called ions, or between electrons and nuclei. The
outermost, or valence, electrons of atoms are the ones mainly
involved in the formation of bonds. The elements within a group
of the periodic table typically have the same number of valence
electrons.
Elements tend to react so as to achieve the stable electron configuration of a noble gas, typically an octet of electrons. A cation, or
positive ion, is formed when an atom loses one or more electrons.
An anion, or negative ion, is formed when an atom gains one or
more electrons. The periodic table is useful in predicting the charges
of ions typically formed by various atoms.
Example Problem 7-1
Determining Charges of Ions
Calcium (Ca, atomic number 20) is an element in group 2 of the
periodic table. Write the electron configuration for a neutral atom of
calcium. Tell how many electrons this atom readily tends to gain or
lose to form an ion. Predict the charge on the ion, write its formula,
and tell whether it is a cation or an anion. Finally, write the electron
configuration of this ion.
A neutral atom of element 20 would have 20 electrons, giving
it the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 . To achieve the
stable electron configuration of a noble gas, the atom would tend
to lose its two valence electrons, producing a cation with a charge
of 2ϩ and the formula Ca 2ϩ . The configuration of this ion would
be 1s 2 2s 2 2p 6 3s 2 3p 6 .