Provide definitions for atoms, elements, periodic table, and sub-atomic particles, and describe the charges and arrangements of sub-atomic particles in an atom.

Here are the solutions to the questions:

Activity 1 - Atoms and sub-atomic particles

1.1
1.1.1 The tiny particles all matter is made up of:

• Atoms

1.1.2 A substance (material) that is made up of atoms of the same kind:

• Element

1.1.3 The organised arrangement of all the known elements:

• Periodic Table

1.1.4 A substance that cannot be broken down into simpler substances:

• Element

1.1.5 Particles, such as protons, neutrons and electrons found in an atom:

• Sub-atomic particles

1.2

a) The three sub-atomic particles are:

• Protons
• Neutrons
• Electrons

b) The charge of each particle:

• Proton: +1
• Neutron: 0 (neutral)
• Electron: -1

1.3
To draw a fluorine atom with 9 protons, 10 neutrons, and 9 electrons:

• Draw a central nucleus containing 9 protons (labeled 'p+') and 10 neutrons (labeled 'n').
• Draw two electron shells around the nucleus.
• Place 2 electrons in the first shell.
• Place 7 electrons in the second shell.
• Label the nucleus and the electron shells.

Activity 2 - Pure substances (Elements and Compounds); Mixtures

2.1
Here are the models for the molecules:

• 2.1.1 H₂: Two small circles (representing Hydrogen atoms) joined together. $$\text{O—O}$$
• 2.1.2 O₂: Two large empty circles (representing Oxygen atoms) joined together. $$\text{◯—◯}$$
• 2.1.3 N₂: Two striped circles (representing Nitrogen atoms) joined together. $$\text{☰—☰}$$
• 2.1.4 H₂O: One large empty circle (Oxygen) bonded to two small circles (Hydrogen). The molecule has a bent shape. $$\begin{matrix} \text{O} \\ \text{/} \quad \text{\\} \\ \text{O} \quad \text{O} \end{matrix}$$
• 2.1.5 CO₂: One solid black circle (Carbon) bonded to two large empty circles (Oxygen). The molecule has a linear shape. $$\text{◯—●—◯}$$