http://www.ck12.org Chapter 8. Ionic and Metallic Bonding
FIGURE 8.3
This image shows the arrangement of electrons in their native, chemically
neutral state. Notice that chromium and manganese have a half-filled d
shell. Copper and zinc have fully filled d shells.with the nearest noble gas. Oxygen will therefore form ions by gaining two electrons to become isoelectronic with
neon, as shown below:
O
[He] 2 s^22 p^4
+2e−→ O^2 −
[He] 2 s^22 p^6 or[Ne]Similarly, nitrogen has five valence electrons in it ground state, which is three electrons away from the nearest noble
gas. Nitrogen can gain three electrons to become isoelectronic with neon:
N
[He] 2 s^22 p^3
+3e−→ N^3 −
[He] 2 s^22 p^6 or[Ne]Example 8.1
Write the ground state configuration for the nonmetal sulfur, and predict the ion it must form to be isoelectronic with
the nearest noble gas.
Answer:
The ground state configuration for the nonmetal sulfur is written as: 1s^2 2s^2 2p^6 3s^2 3p^4. Sulfur has 16 electrons. The
nearest noble gas to sulfur is argon, which has an electron configuration of: 1s^2 2s^2 2p^6 3s^2 3p^6. To be isoelectronic
with argon, which has 18 electrons, sulfur must gain two electrons. Therefore sulfur will form a 2- ion, becoming
S^2 −.
Lesson Summary
- Atoms or groups of atoms that carry an overall electrical charge are referred to as ions. Cations can be formed
when a neutral species loses electrons, while anions are formed when a neutral species gains electrons. - Particularly for main group elements, the number of electrons a given element has in its outer (valence) shell
largely determines the chemical behavior of that element. - The octet rule states that atoms will lose, gain, or share electrons to achieve the electron configuration of the