The Periodic Table (AQA GCSE Chemistry)

John Newlands first began developing the idea of a periodic table of elements around 140 years ago.

He jotted down the elements known at that time in order, starting with the lightest atoms.

From here he arranged them into seven groups as shown in Figure 1 below. 

Figure 1

There are differences between the groups in Newlands’ periodic table and those in the modern day table. 

Write down three of these differences, basing your comparisons up to the element calcium.

Suggest a reason why this part of Newlands' table differed from the modern version.

Some time later Dimitri Mendeleev developed the periodic table of the elements. 

In his version he arranged the elements according to their relative atomic masses and properties.

Where Mendeleev put tellurium (Te) and iodine (I) in his table is indicated in Figure 2 below. 

He placed them in these positions because of their properties.

Figure 2

Identify the error in this arrangement of tellurium and iodine.

In the modern periodic table this arrangement is not a problem.

Explain why not.

The electronic structures of atoms from three different elements are shown.

    2,8,1                         2,8,8                        2,8,8,1
element W               element Y                  element Z

Name the elements W, Y and Z.

Explain why element Z is more reactive than element W.

Explain why element Y is unreactive.

Iodine is found above astatine in Group 7 of the periodic table.

What is its formula and state at room temperature?

The diagram shows the electron structures of some elements.

Which two elements have similar chemical properties?

Sodium and potassium are both alkali metals.

Explain in terms of their electronic structures, why both elements are placed in Group 1 in the periodic table.

Use the Data Sheet to answer this question.

The electronic structures of some atoms and ions are shown in Figure 1 below.

Figure 1

Which structure represents an atom of sodium?

Which structure represents a potassium ion?

All of the alkali metals react with cold water.

Lithium reacts as follows:

lithium + water → lithium hydroxide + hydrogen

Complete and balance the symbol equation for this reaction.

__________  +  __________  →  2LiOH  +  __________

Potassium and sodium also react with water but the observed reactions are not the same. 

How does the reactivity of potassium differ from sodium?

State one difference in their electronic structures which explains the difference in reactivity between potassium and sodium.

The Group 1 metals have similar chemical properties.

Describe one chemical reaction that could be used to show that lithium, sodium and potassium have similar chemical properties. 

State the reactant you would use and the substances produced.

All of the halogens react with hydrogen but there are differences in their reactivity.

Fluorine reacts explosively at very low temperatures and in the absence of light.

Chlorine reacts explosively at room temperatures but requires light.

Bromine requires light and a temperature of around 200 ^oC to react.

Given the above information, suggest and explain the conditions required for hydrogen and iodine to react.

Explain the trend in reactivity in the Group 7 elements with reference to their electronic structures.

Table 1 below gives the melting points of some of the elements of Group 7.

Table 1

Using the information in Table 1, predict a value for the melting point of astatine.

State which halogens are solids at 40 °C.

Draw a diagram to show how the electrons are arranged in an atom of fluorine.

As for the alkali metals, the Group 7 elements all have similar chemical properties.

Using their electron arrangements, give a reason for their similarity.

Xenon is an unreactive element. 

Explain why xenon is so unreactive.

When sodium reacts with water an alkaline solution is formed.

Which statement explains why this happens?

Fluorine reacts with most elements but does not react with argon.

The atomic number of fluorine is 9, chlorine is 17 and argon is 18.

In which group of the periodic table are fluorine and chlorine placed?

Draw a diagram to show the electron arrangement of an atom of chlorine.

Explain why fluorine is more reactive than chlorine.

An electric light bulb is shown in Figure 1 below. 

The tungsten filament conducts electricity when the light is switched on and heats up to a high temperature, giving off light.

Figure 1

The bulb has a closed atmosphere containing argon only. 

What reaction would occur if air was used instead of argon?

With reference to the electronic structure of the argon atom, explain why it is used in light bulbs.

Mendeleev classified the known elements into a table by ordering them by their atomic weights.

His periodic table was published in 1869 and it showed the elements that had been discovered at that time.

Part of his periodic table is shown in Table 1.

Use the information in Table 1 and your periodic table to answer the questions.

Table 1

Hydrogen is an element from Mendeleev's table that is not in the same group of the modern periodic table.

Give two reasons why it should not be in Group 1.

Give two reasons why hydrogen could be placed in Group 1.

Give two reasons why hydrogen could be placed in Group 7.

The modern periodic table arranges the elements in order of atomic number.

What scientific discoveries allowed elements to be placed in their correct period and group?

How did this knowledge allow elements to be correctly placed?

The halogens are found in Group 7 of the periodic table.

Table 1 shows the melting point and boiling point of some of the halogens.

Table 1

What is the state of chlorine at -100 ^oC and at 0 ^oC? 

State at -100 ^oC: ____________________

State at 0 ^oC: ____________________

Explain why the boiling point of the Group 7 elements increases as you go down the group as shown in Table 1.

The halogens all react with hydrogen to form the corresponding hydrogen halide.

Explain why the halogens all react in a similar way.

Predict and explain the difference in the rate of the reaction between hydrogen with chlorine and between hydrogen and iodine.

This question is about Group 1 metals.

The reaction between three Group 1 metals, lithium, sodium and potassium, with water was demonstrated by a teacher.

The teacher added a few drops of universal indicator to water in a trough. They then dropped a small piece of the Group 1 metal into the water.

Write the balanced symbol equation for the reaction between lithium and water.

In terms of electronic structure, state and explain the difference in reactivity between potassium and water compared with lithium and water.

State what colour the universal indicator turned when potassium was added to water and explain why it changes to this colour.

Element Z has the following properties:

• It is a solid at room temperature
• Does not conduct heat or electricity
• Forms simple molecules with non-metals
• Forms giant ionic lattices with metals in which it has a 1- ion

Select the formula of the compound formed when element Z reacts with calcium from the list below.

Explain your answer using the information provided.

Calcium is a Group 2 metal. Group 2 metals show similar trends in reactivity to Group 1 metals as you go down the group. 

Magnesium is another Group 2 metal.

Explain why, in terms of atomic structure, magnesium reacts in a similar way to calcium with element Z but it is less reactive than calcium.

Table 1 shows the electronic structures of five elements.

The letters are not the chemical symbols of the element.

Table 1

Give the letters of two elements that belong to the same group in the periodic table.

State the group that they belong to.

Use Table 1 and the periodic table.

Give a letter of the element that can form a giant covalent structure when reacted with oxygen.

State the name of the giant covalent structure formed.

Use Table 1 and the periodic table.

Give the letter of the element that is monatomic.

Explain your answer.

Give the letters of two elements that are gases at room temperature.

A student carried out a displacement reaction using an unknown halogen and a salt containing a halide ion.

As the reaction progressed they observed the formation of a dark brown solution.

Which halogen and salt did the students react together?