# Question #d1001

Jun 16, 2015

You draw concentric circles, each with the appropriate number of electrons.

#### Explanation:

Sodium Oxide

The electron configuration of $\text{Na}$ is (2, 8, 1). It can achieve a noble gas octet by donating its outer electron to another atom.

The electron configuration of $\text{O}$ is (2, 6). It can achieve a noble gas octet by accepting an electron from each of two sodium atoms (excuse my hand-drawn diagrams).

The opposite charges create electrostatic attractions between the ${\text{Na}}^{+}$ and ${\text{O}}^{2 -}$ ions.

Calcium Sulfide

The electron configuration of $\text{Ca}$ is (2, 8, 8, 2). It can achieve a noble gas octet by donating its two outer electrons to another atom.

The electron configuration of $\text{S}$ is (2, 8, 6). It can achieve a noble gas octet by accepting two electrons into its outer shell.

The opposite charges create electrostatic attractions (ionic bonds) between the ${\text{Ca}}^{2 +}$ and ${\text{S}}^{2 -}$ ions.

Hydrogen Bromide

The electron configuration of $\text{H}$ is (1). It can achieve a helium configuration by sharing its outer electron with another atom.

The electron configuration of $\text{Br}$ is (2, 8,18, 7). It can achieve a noble gas octet by sharing an outer electron with $\text{H}$.

The sharing of electrons makes a covalent bond.

Ethene

The electron configuration of $\text{H}$ is (1). It can achieve a helium configuration by sharing its outer electron with another atom.

The electron configuration of $\text{C}$ is (2, 6). It can achieve a noble gas octet by sharing its outer electrons with other atoms.

The sharing of two electrons makes a covalent $\text{C-H}$ bond. the sharing of four electrons makes a covalent $\text{C=C}$ double bond.