Define the following terms: a. Neutral atom b. Element c. Molecule Give (3) examples of a. Element b. Molecule State the bond found in the following Compounds: (i) ZnO (ii) Al2O3 (iii) CaCl2 With the aid of a diagram explain the formation BeCl2.

Step 1a: Definition of covalent bond

A covalent bond is a chemical bond formed when two atoms share one or more pairs of valence electrons to achieve stable electron configurations.

Step 1b: Definition of covalent compounds

Covalent compounds are substances composed of molecules formed by covalent bonds between non-metal atoms. They typically have low melting and boiling points and do not conduct electricity in any state.

Examples: $H_2O$ (water), $CO_2$ (carbon dioxide), $CH_4$ (methane).

Step 1c: Definition of ionic bond and compounds where found

An ionic bond is a chemical bond formed by the electrostatic attraction between oppositely charged ions, resulting from the complete transfer of electrons from a metal atom (forms cation) to a non-metal atom (forms anion).

Ionic bonds are found in the following compounds: $\mathrm{NaCl}$ (sodium chloride), $\mathrm{KCl}$ (potassium chloride), $\mathrm{MgO}$ (magnesium oxide), $\mathrm{CaCl_2}$ (calcium chloride).

Step 2: Bond found in the following compounds (common examples)

Assuming typical examples like:

a. $\mathrm{NaCl}$: Ionic bond.

b. $HCl$: Covalent bond (polar).

c. $H_2O$: Covalent bonds.

d. $\mathrm{AlCl_3}$: Covalent bond (if listed).

Step 3: Formation of ionic bond with diagram (e.g., $\mathrm{NaCl}$)

Ionic bond formation in $\mathrm{NaCl}$:

Sodium (Na, group 1, 1 valence electron) loses 1 electron to achieve stable octet.

Chlorine (Cl, group 17, 7 valence electrons) gains 1 electron to achieve stable octet.

The $\mathrm{Na}^{+}$ and $\mathrm{Cl}^{-}$ ions are held together by strong electrostatic attraction.

Diagram description (Lewis structure):

Na atom: $[Na] \cdot$ (1 dot)

loses dot → $[Na^{+}]$

Cl atom: $:\ddot{Cl}\cdot$ (7 dots)

gains dot → $[:\ddot{Cl}:]^{-}$

Ionic lattice: $\mathrm{Na}^{+} Cl^{-} Na^{+} \ldots$

Step 4: Formation of covalent bond with diagram (e.g., $H_2$)

Two hydrogen atoms each with 1 valence electron share a pair.

Shared pair (single bond) allows both to have duet.

For $H_2O$:

Oxygen shares 1 electron with each H.

Lewis: Central O with two lone pairs, single bonds to two H.

(Note: Simple text representation; actual diagram shows dots for shared pairs.)