Introduction to the Periodic Table

The Periodic Table is a chart that organises all known elements in order of increasing atomic number (the number of protons in the nucleus of an atom). It’s one of the most important tools in chemistry, as it helps scientists understand the properties and relationships between elements.

In Year 8 science, we’ll focus on learning about the basic structure of the Periodic Table, groups and periods, and the types of elements it contains.

Key Concepts of the Periodic Table

1. Organisation: Elements are arranged in order of increasing atomic number from left to right and top to bottom.
2. Groups: The vertical columns in the table are called groups. Elements in the same group have similar properties and the same number of electrons in their outer shell.
3. Periods: The horizontal rows are called periods. As you move across a period, the atomic number increases by one.
4. Metals and Non-Metals: The Periodic Table is split into metals on the left and non-metals on the right. The zig-zag line separates these types.
5. Special Groups:

• Group 1: The alkali metals, which are highly reactive metals.
• Group 7: The halogens, which are reactive non-metals.
• Group 0 (or Group 18): The noble gases, which are very unreactive.

The Periodic Table not only shows the symbols and atomic numbers of elements but also allows us to predict their properties, such as reactivity and state at room temperature.

Exam Questions on the Periodic Table

To assess your understanding of the Periodic Table, here are 20 questions each at easy, medium, and hard levels.

Easy Level Questions

Basic Understanding of the Periodic Table

1. What is the Periodic Table?
2. In what order are elements arranged in the Periodic Table?
3. What is a group in the Periodic Table?
4. What is a period in the Periodic Table?
5. Where are metals generally found on the Periodic Table?
6. What does each element’s atomic number represent?
7. What is the symbol for oxygen?
8. In which group are the noble gases found?
9. What is the symbol for hydrogen?
10. Are non-metals found on the left or right of the Periodic Table?
11. What is the group number for alkali metals?
12. What is the atomic number of helium?
13. What element has the symbol ‘Na’?
14. What is the name of Group 1 elements?
15. What is the name of Group 7 elements?
16. Is gold a metal or non-metal?
17. What element has the symbol ‘Fe’?
18. Are noble gases reactive or unreactive?
19. What does each element symbol consist of?
20. What is the name of Group 0 elements?

Medium Level Questions

Intermediate Knowledge and Trends in the Periodic Table

1. Why are elements in the same group similar?
2. Explain why Group 1 elements are very reactive.
3. Describe the trend in reactivity as you move down Group 7.
4. What type of elements are found in Group 7?
5. Why are elements arranged by atomic number in the Periodic Table?
6. Which element has the atomic number 12?
7. What happens to the atomic size as you go down a group?
8. Why is the Periodic Table useful in chemistry?
9. Name two elements in the same period as oxygen.
10. What happens to the number of protons as you move across a period?
11. Which element is located in Period 2, Group 1?
12. Describe one property of noble gases.
13. What is the symbol for potassium?
14. Why are noble gases unreactive?
15. What element is in Group 2, Period 3?
16. How does reactivity change as you go down Group 1?
17. Explain why halogens are reactive.
18. Which group contains the least reactive elements?
19. Describe the location of non-metals in the Periodic Table.
20. Why do elements in Group 1 react similarly with water?

Hard Level Questions

Advanced Concepts and Applications

1. Explain the trend in atomic radius as you move across a period.
2. Why does reactivity increase as you move down Group 1?
3. Describe the electron arrangement in a Group 1 atom.
4. Explain why Group 0 elements have full outer shells.
5. How does electronegativity change across a period?
6. Why do metals generally have lower electronegativity than non-metals?
7. Explain the significance of valence electrons in determining group properties.
8. What is the atomic structure difference between a metal and a non-metal?
9. Why are elements in Group 1 stored in oil?
10. Explain why transition metals are often used as catalysts.
11. Describe how the ionisation energy changes down Group 7.
12. What is the electron configuration of chlorine?
13. Explain why alkali metals react with halogens to form salts.
14. Why does fluorine have a high electronegativity?
15. How are elements in the same group related in terms of electron configuration?
16. Why is helium placed in Group 0 despite having only two electrons?
17. Describe the properties that distinguish transition metals from Group 1 metals.
18. Why are some elements arranged in a staircase line on the Periodic Table?
19. How does the shielding effect influence reactivity in Group 1 and Group 7?
20. Explain the concept of periodicity in the Periodic Table.

Answers and Explanations

Easy Level Answers

1. A chart that organises all known elements – The Periodic Table arranges elements by increasing atomic number.
2. By increasing atomic number – Elements are organised by atomic number from left to right.
3. A vertical column – Elements in the same group have similar properties.
4. A horizontal row – Elements in the same period have increasing atomic numbers.
5. On the left – Metals are generally found on the left side of the table.
6. The number of protons – The atomic number is the number of protons in an element’s nucleus.
7. O – The chemical symbol for oxygen is O.
8. Group 0 – Noble gases are found in Group 0 or Group 18.
9. H – The symbol for hydrogen is H.
10. On the right – Non-metals are generally found on the right side of the table.
11. Group 1 – The alkali metals are in Group 1.
12. 2 – Helium has an atomic number of 2.
13. Sodium – The symbol ‘Na’ represents sodium.
14. Alkali metals – Group 1 elements are known as alkali metals.
15. Halogens – Group 7 elements are called halogens.
16. Metal – Gold is a metal.
17. Iron – The symbol ‘Fe’ represents iron.
18. Unreactive – Noble gases are generally unreactive.
19. One or two letters – Element symbols are made up of one or two letters.
20. Noble gases – Group 0 elements are known as noble gases.

Medium Level Answers

1. Same number of outer electrons – Elements in the same group have similar chemical properties.
2. They have one electron in their outer shell – This makes it easy for them to lose it and react.
3. Reactivity decreases – As you move down Group 7, reactivity decreases.
4. Non-metals – Group 7 elements are non-metals.
5. Atomic number shows the number of protons – It helps organise elements systematically.
6. Magnesium – The element with atomic number 12 is magnesium.
7. Atomic size increases – More electron shells are added as you go down a group.
8. It predicts properties and behaviours of elements.
9. Nitrogen and fluorine – Both are in the same period as oxygen.
10. It increases – The number of protons increases across a period.
11. Lithium – Lithium is in Period 2, Group 1.
12. Very unreactive – Noble gases are known for their lack of reactivity.
13. K – Potassium’s symbol is K.
14. Full outer electron shells – This makes noble gases stable.
15. Magnesium – It is found in Group 2, Period 3.
16. Reactivity increases down Group 1 due to weaker attraction on the outer electron.
17. They need one electron to complete their outer shell.
18. Group 0 (noble gases) – The least reactive elements are found in this group.
19. On the right side of the table
20. **They all have one outer electron** which reacts similarly with water.

Hard Level Answers

1. Atomic radius decreases across a period due to increasing positive charge attracting electrons more strongly.
2. The outer electron is further from the nucleus – It is easier to lose as you go down Group 1.
3. One electron in the outer shell – This makes Group 1 elements highly reactive.
4. Their electron shells are complete – This makes Group 0 elements stable and unreactive.
5. Electronegativity increases – As you go across a period, atoms attract electrons more strongly.
6. Metals tend to lose electrons – This results in lower electronegativity.
7. Valence electrons determine an element’s reactivity and placement in groups.
8. Metals have free electrons, non-metals have fixed electrons – This influences their properties.
9. To prevent reaction with air or water – Group 1 metals are very reactive.
10. They have a high surface area for chemical reactions – Transition metals are often catalysts.
11. Ionisation energy decreases down Group 7 – Outer electrons are further from the nucleus.
12. 1s² 2s² 2p⁶ 3s² 3p⁵ – The electron configuration of chlorine.
13. They need one electron to complete their outer shell – Halogens form ionic bonds with alkali metals.
14. It has a small atomic radius and a strong nuclear pull on electrons.
15. Elements in the same group have similar electron configurations.
16. It has a full outer shell with only two electrons.
17. Transition metals are harder and have higher densities than Group 1 metals.
18. The staircase line separates metals from non-metals.
19. The shielding effect reduces the attraction of the nucleus on outer electrons.
20. Periodicity refers to recurring trends in properties across periods and groups.

These questions and answers provide Year 8 students with an overview of the Periodic Table, helping them understand key concepts and trends and preparing them effectively for their Key Stage 3 exams.