3.4 Groups and periods

Summary: Palladium is a metal. What can you predict about its properties? Tags: science oxford-science student-book-7 chemistry Created: 2026-05-19 Last Updated: 2026-05-19

After this topic, you will be able to:

• give the group and period numbers of Elements
• use data from tables or bar charts to describe patterns in the properties of elements in groups or periods
• use data to predict the properties of another element in a group or period.

Think back

1. Where in the Periodic Table are the non-metal elements?
2. Name two metal elements.
3. What does melting point mean?

Key idea The Periodic Table organizes elements into columns called groups (e.g. Group 1) and rows called periods (e.g. Period 4).

Key words group, period

Palladium is a metal. What can you predict about its properties?

Figure 1 shows that palladium is shiny. You might have predicted that it is a good conductor of thermal Energy (heat) and of electricity. If you find palladium in the Periodic Table, you can make even better predictions.

Figure 1Palladium is a metal element. It is used in catalytic converters in cars, in tools used for surgery in hospitals, and in some musical instruments.

What are groups?

In the Periodic Table, the columns are called groups. Figure 2 shows some groups of the Periodic Table. For example, the elements beryllium (Be) and magnesium (Mg) are in Group 2.

Figure 2Some groups of the Periodic Table. Full text alternative to the content

The elements in a group have similar physical and chemical properties. Going down a group, there are patterns in properties.

A The chemical symbol of tin is Sn. Give the group number of tin.

Tables 1, 2, and 3 show data for elements near palladium in the Periodic Table. Each table shows the elements in one group. Tables 1, 2, and 3 Melting points of elements in three groups of the Periodic Table. Element

Melting point in ͦC

iron

1535

ruthenium

2500

osmium

3000

Element Melting

point in ͦC

cobalt

1492

rhodium

1970

iridium

2440

Element

Melting point in ͦC

nickel

1453

palladium

platinum

1769

Sophie studies the data. She makes this prediction:

For the groups with iron and cobalt, melting point increases from top to bottom. The group with nickel is likely to show the same pattern. So I predict that the melting point of palladium is between 1453 °C and 1769 °C.

A data book gives the melting point of palladium as 1550 °C. Sophie’s prediction is correct.

B Describe the pattern in melting points of the elements in Table 1.

What are periods?

The rows of the Periodic Table are called periods. Figure 3 shows some periods of the Periodic Table.

Figure 3Some periods of the Periodic Table. Full text alternative to the content

Going across a period, there are patterns in the properties of the elements. Figures 4 and 5 show some of these patterns.

Figure 4The melting points of Period 2 elements. Full text alternative to the content

Figure 5The melting points of Period 3 elements. Full text alternative to the content

Amara describes the patterns in Figure 4.

For Period 2, the melting point increases from left to right for the first four elements. The others have low melting points.

C The chemical symbol of silver is Ag. Give its period number.

Table 4 Table 4 shows the sizes of Atoms of some Group 1 elements. Draw a bar chart to show these data. Table 4 Sizes of Group 1 element atoms. Group 1 element Relative atomic radius lithium 15 sodium 18 potassium 23 rubidium 24

Stretch zone

1. Copy and complete the sentences. The columns of the Periodic Table are groups/periods. The rows are groups/periods.
2. Table 5 gives the densities of three elements in the same group of the Periodic Table. Describe the pattern in density, from top to bottom of the group. Table 5Element Density in g/cm3 cobalt 8.9 rhodium 12.4 iridium 22.5

Stretch zone

1. Compare the patterns in Figures 4 and 5.