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The periodic table
This topic connects periodic table position to atomic number, outer electrons, metal and non-metal behaviour, historical development and group trends.
45
Objectives
225
Flashcards
225
Questions
90 min
Study time
AQAGCSEChemistryAtomic structure and the periodic table
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45 objective pages available
The periodic table6 objectives
- Describe how elements are arranged in order of atomic number in the modern periodic table.
- Explain that columns in the periodic table are called groups.
- Explain that elements in the same group have the same number of outer-shell electrons.
- Explain how outer-shell electrons give elements in the same group similar chemical properties.
- Explain how the position of an element in the periodic table relates to electron arrangement and atomic number.
- Predict possible reactions and likely reactivity from an element's position in the periodic table.
Development of the periodic table8 objectives
- Describe how early scientists arranged elements by atomic weight before subatomic particles were discovered.
- Explain why early periodic tables were incomplete.
- Explain why some elements were placed in inappropriate groups when atomic weight order was followed strictly.
- Describe how Mendeleev left gaps for undiscovered elements.
- Explain how Mendeleev changed some element orders based on chemical properties.
- Explain how discovery of predicted elements supported Mendeleev's table.
- Explain how knowledge of isotopes helped explain why atomic weight order was not always correct.
- Explain how testing predictions can support or refute scientific ideas.
Metals and non-metals7 objectives
- Define metals as elements that react to form positive ions.
- Explain that non-metals do not form positive ions.
- Describe where metals are found in the periodic table.
- Describe where non-metals are found in the periodic table.
- Explain differences between metals and non-metals using physical and chemical properties.
- Explain how atomic structure relates to whether an element is a metal or non-metal.
- Explain how reactions of elements relate to electron arrangement and atomic number.
Group 06 objectives
- Identify Group 0 elements as noble gases.
- Explain why noble gases are unreactive in terms of stable electron arrangements.
- State that helium has two electrons in its outer shell while the other noble gases have eight.
- Explain why noble gases do not easily form molecules.
- Describe the trend in boiling points of the noble gases down Group 0.
- Predict properties of Group 0 elements from trends down the group.
Group 18 objectives
- Identify Group 1 elements as alkali metals.
- Explain that Group 1 elements have one electron in their outer shell.
- Describe reactions of lithium, sodium and potassium with oxygen.
- Describe reactions of lithium, sodium and potassium with chlorine.
- Describe reactions of lithium, sodium and potassium with water.
- Explain why Group 1 elements have similar chemical properties.
- Describe and explain why reactivity increases down Group 1.
- Predict properties of Group 1 elements from trends down the group.
Group 710 objectives
- Identify Group 7 elements as halogens.
- Explain that halogens have seven electrons in their outer shell.
- Describe halogens as non-metals that exist as molecules made of pairs of atoms.
- Describe compounds formed when chlorine, bromine and iodine react with metals.
- Describe compounds formed when chlorine, bromine and iodine react with non-metals.
- Describe the trend in relative molecular mass down Group 7.
- Describe the trends in melting point and boiling point down Group 7.
- Describe and explain why reactivity decreases down Group 7.
- Explain displacement reactions between halogens and halide salts.
- Predict properties of Group 7 elements from trends down the group.
Key terms
atomic numberperiodic tablegroupouter-shell electronssimilar chemical propertieselectron arrangementreactivityatomic weightMendeleevincomplete periodic tablesarrangement by atomic weightinappropriate groups
Exam tips
- Understand Atomic Number: Remember to memorize that elements are arranged in the periodic table by increasing atomic number, which is the number of protons in the nucleus. Link your answer to The periodic table in The periodic table, and keep the chemistry specific to periodic table.
- Understand Group Characteristics: Remember to memorize that elements in the same group have the same number of outer-shell electrons. Link your answer to The periodic table in The periodic table, and keep the chemistry specific to periodic table.
Common mistakes
- Misunderstanding Atomic Number Arrangement: Remember that the modern periodic table arranges elements in order of increasing atomic number, which is the number of protons in the nucleus.
- Misunderstanding Groups: Remember that groups are the vertical columns in the periodic table, while periods are the horizontal rows. Focus on the vertical arrangement when discussing groups.
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