Identify the elements based on their properties and atomic structure. Draw the atomic structure of Lithium.

SECTION B

QUESTION 3

3.1.1. Oxygen: $\boxed{\text{O}}$
3.1.2. Nitrogen: $\boxed{\text{N}}$

3.2.1. Is a non-metal in group 1: $\boxed{\text{Hydrogen}}$
3.2.2. Is represented by the symbol Na: $\boxed{\text{Sodium}}$
3.2.3. It has six protons in a nucleus of one atom: $\boxed{\text{Carbon}}$
3.2.4. It is a noble gas in period 2: $\boxed{\text{Neon}}$
3.2.5. It is in group 2 period 3: $\boxed{\text{Magnesium}}$

3.3. a) Sodium Chloride:
Sodium chloride (NaCl) is composed of sodium atoms (Na) and chlorine atoms (Cl).
You would recover $\boxed{\text{2 different atoms}}$.

3.4. Draw the labelled atomic structure with three protons, four neutrons and three electrons.
This describes a Lithium atom.

• The nucleus contains 3 protons (positively charged) and 4 neutrons (no charge).
• The 3 electrons (negatively charged) orbit the nucleus in electron shells.
• The first electron shell holds 2 electrons, and the second electron shell holds 1 electron.

A description of the drawing:

• Draw a central circle representing the nucleus. Inside, label "3 Protons" and "4 Neutrons".
• Draw a smaller circle around the nucleus representing the first electron shell. On this circle, draw and label "2 Electrons".
• Draw a larger circle around the first shell representing the second electron shell. On this circle, draw and label "1 Electron".

QUESTION 4

4.1. Which diagram A, B or C represents a diatomic molecule? Give a reason for your answer.

• A.
• Reason: Diagram A shows individual units, each consisting of two identical atoms chemically bonded together. This is the definition of a diatomic molecule.