2 What have I learned about elements, atoms, and compounds?

Summary: Tags: science oxford-science student-book-7 chemistry Created: 2026-05-19 Last Updated: 2026-05-19

In this chapter, you have:

• learned about Elements and used an international code to identify them
• found out about the tiny particles – Atoms – that make up elements, and how they join together in different ways to make up all the substances on Earth and in the Universe
• discovered that every material is made from atoms of one or more of the hundred or so elements that exist.

Journey through elements, atoms, and Compounds What do I already know? - Reversible and irreversible change

• Energy changes and reactions This chapter - 2.1 Elements
• 2.2 Atoms
• 2.3 Compounds
• 2.4 Chemical Formulae What comes next? - Three elements
• Physical and chemical properties of metals and non-metals
• Elements of Groups 1, 7, and
• Inside atoms
• Elements, compounds, and Mixtures
• Chemical Reactions

Table 2

1. Give the definitions of the key words. element (1 mark)atom (1 mark)compound (1 mark)molecule (1 mark)
2. Mobile phones store electrical charge in capacitors. Capacitors contain a mixture of tantalum and tantalum oxide. Tantalum is an element. Give the number of types of atom in tantalum. (1 mark)Tantalum oxide is a compound of two elements. One of the elements is tantalum. Name the other element. (1 mark)Write down the number of types of atom in tantalum oxide. (1 mark)Copy and complete the sentences. The formula of tantalum oxide is Ta2O5. This means that there are blank atoms of tantalum for every five atoms of blank. (2 marks)
3. Figure 1 shows a molecule of sulfur dioxide. Each shape represents one atom. Different coloured shapes represent atoms of different elements. Figure 1 Give the total number of atoms in the molecule. (1 mark)Give the number of different types of atom in the molecule. (1 mark)State whether sulfur dioxide is an element or a compound. Explain your decision. (2 marks)Copy and complete Table 1. (3 marks) Table 1Name of element Number of atoms of this element in one sulfur dioxide molecule sulfurWrite the formula of sulfur dioxide. (2 marks)
4. Table 2 shows data for six elements. Figure 2 shows their positions in the Periodic Table. Figure 2 Full text alternative to the content Table 2Name of element Chemical symbol Melting point (˚C) lithium Li 180 sodium Na 98 potassium K 64 neon Ne −249 argon Ar −189 krypton Kr −157 Draw a bar chart to display the melting point data for the Group 1 elements. (3 marks)Compare the melting point patterns for the Group 1 and Group 0 elements. (4 marks)