ivana
How to Use These Notes
These notes are designed to replace your textbook. Each major topic from the provided pages is broken down into clear sections with all the key details, definitions, and explanations you need for your test.
---
Module 3: The Periodic Table
Topic 3.1: Periodic Table Basics
Learning Intention: Describe what the periodic table tells us about each element.
1. Key Concepts
· The periodic table organises all known elements.
· Each element has a unique square that provides key information.
· Chemical symbols are a universal language for scientists.
· Information in the square relates to the structure of an atom.
2. Definitions
· Periodic Table: A table of all known elements and their chemical symbols, arranged in order of increasing atomic number.
· Element: A pure substance made of only one type of atom.
· Chemical Symbol (X): A one or two-letter abbreviation used to represent an element (e.g., H for hydrogen, Ag for silver).
· Atomic Number (Z): The number of protons in the nucleus of an atom.
· Atomic Mass: The average mass of the atoms in a sample of an element, measured in atomic mass units (amu).
· Electron Shell: The space around an atom’s nucleus where electrons circulate at different energy levels.
· Electron Configuration: The number of electrons in each shell of an atom, written starting with the smallest shell (e.g., 2, 8, 8, 2).
· Isotopes: Atoms of the same element that have the same number of protons but a different number of neutrons.
3. Explanations
· The Role of Chemical Symbols: Chemical symbols allow scientists from all over the world to communicate clearly, regardless of their spoken language. For example, silver is known as 'Ag' everywhere, even though its name is 'argent' in French and 'plata' in Spanish.
· Information in an Element's Square: Each square on the periodic table is a data box containing four key pieces of information:
1. Atomic Number (Z): Located at the top of the square.
2. Chemical Symbol (X): The large central letter(s).
3. Element Name: The full name of the element.
4. Atomic Mass: Located at the bottom of the square.
· Atomic Number = Proton Number: The atomic number is the fundamental identifier of an element. If an atom has 14 protons, it must be a silicon atom. If it has 56 protons, it must be a barium atom.
· Neutral Atoms: Atoms are neutral, meaning they have no overall electrical charge. This is because the number of negatively charged electrons is equal to the number of positively charged protons.
· Electron Configuration (2,8,8,2): Electrons are arranged in shells around the nucleus. They fill the shells closest to the nucleus first.
· The first shell can hold a maximum of 2 electrons.
· The second shell can hold a maximum of 8 electrons.
· The third shell can hold a maximum of 8 electrons (for the first 20 elements).
· The fourth shell holds the remaining electrons.
· Example: A calcium atom (20 electrons) has a configuration of 2, 8, 8, 2.
· Atomic Mass is an Average: The atomic mass on the table is not the mass of a single atom. It is the weighted average mass of all the different isotopes of that element found in a typical sample.
4. Important Facts to Memorise
· There are 118 known elements, arranged from atomic number 1 (hydrogen) to 118 (oganesson).
· An atom has the same number of electrons and protons.
· Most of an atom's mass is in the nucleus (protons + neutrons).
· Isotopes exist because the number of neutrons can vary.
· The electron shells fill in a specific order: 2, then 8, then 8 (for the first 20 elements).
5. Diagrams
· Figure 3.4: The Element Square: A diagram showing a square from the periodic table. It is labelled with:
· Atomic number (Z) at the top.
· Chemical symbol (X) in the centre.
· Element name below the symbol.
· Atomic mass at the bottom.
· Figure 3.5: Lithium Atom: A diagram showing a lithium atom. It has 3 protons and 4 neutrons in the central nucleus. Two electrons orbit in the first shell, and one electron orbits in the second shell.
· Figure 3.6: Calcium Atom: A diagram showing a calcium atom with 20 electrons distributed across four shells. The first shell has 2, the second has 8, the third has 8, and the fourth (valence shell) has 2. The diagram shows electrons pairing up as the shells fill.
· Figure 3.7: Carbon Isotopes: Three diagrams side-by-side showing the nuclei of Carbon-12, Carbon-13, and Carbon-14. All have 6 protons, but they have 6, 7, and 8 neutrons respectively. All have 6 electrons.
6. Examples
· Sodium (Na): Symbol comes from the Latin word natrium.
· Iron (Fe): Symbol comes from the Latin word ferrum.
· Potassium (K): Symbol comes from the Latin word kalium.
· Strontium (Sr): Named after a Scottish village, Sròn an t-Sìthein.
· Calcium (Ca): Atomic number 20 means it has 20 protons and, in a neutral atom, 20 electrons.
7. Test Tips
· Be able to read any element's square and identify the atomic number, symbol, name, and atomic mass.
· Be able to calculate the number of protons, neutrons, and electrons in a neutral atom, given its atomic number and mass number (e.g., for an atom with Z=11 and an atomic mass of 23 amu, it has 11 p⁺, 11 e⁻, and 12 n⁰).
· Remember that the atomic mass on the table is an average because of isotopes.
---
Topic 3.2: Organisation of Elements
Learning Intention: Describe how elements are organised in the periodic table and predict relative reactivity.
1. Key Concepts
· Elements are arranged in order of increasing atomic number.
· The table is organised into vertical columns (groups) and horizontal rows (periods).
· The position of an element is directly linked to the structure of its atoms.
· Reactivity trends can be predicted based on an element's position.
2. Definitions
· Group: A vertical column (1-18) in the periodic table. Elements in the same group have similar chemical properties.
· Period: A horizontal row (1-7) in the periodic table. Elements are placed in a period in order of increasing atomic number.
· Valence Shell: The outermost electron shell of an atom (the shell furthest from the nucleus).
· Valence Electrons: The electrons found in the outermost (valence) shell of an atom.
· Reactive: Describes an element that undergoes chemical reactions easily.
3. Explanations
· Groups and Valence Electrons: Elements in the same group have the same number of valence electrons. This is why they have similar chemical properties.
· Group 1: 1 valence electron
· Group 2: 2 valence electrons
· Group 13: 3 valence electrons
· Group 14: 4 valence electrons
· Group 15: 5 valence electrons
· Group 16: 6 valence electrons
· Group 17: 7 valence electrons
· Group 18: 8 valence electrons (full outer shell)
· Groups 3-12 (Transition Metals): The number of valence electrons can vary.
· Periods and Electron Shells: The period number an element is in tells you how many occupied electron shells its atoms have.
· Period 1 elements have 1 electron shell.
· Period 2 elements have 2 electron shells.
· Period 3 elements have 3 electron shells, and so on.
· Atomic Size Trend: As you go down a group, atoms gain another electron shell. This makes the atom larger. Therefore, atomic size increases down a group.
· Reactivity Trends:
· Metals: Reactivity increases as you move down a group and to the left across a period. The most reactive metals are in the bottom-left corner (e.g., Francium).
· Non-metals: Reactivity increases as you move up a group and to the right across a period. The most reactive non-metal is Fluorine (F), in the top-right corner.
· Noble Gases (Group 18): Are unreactive because they already have a full outer shell of 8 electrons (2 for Helium).
4. Important Facts to Memorise
· The periodic table has 7 periods and 18 groups.
· The two separate rows at the bottom are the lanthanoids (elements 57-71) and actinoids (elements 89-103). They are placed there so they don't make the table too wide.
· Group 1: Alkali Metals: Very reactive, soft, shiny, malleable, good conductors. React violently with water and air (stored in oil).
· Group 2: Alkaline Earth Metals: Reactive, but less so than Group 1. Have similar properties to alkali metals.
· Groups 3-12: Transition Metals: Hard, shiny, good conductors. Can form many brightly coloured compounds. Mercury (Hg) is the only liquid one at room temperature.
· Groups 13-16: Metalloids: (e.g., Boron, Silicon) Have properties of both metals and non-metals.
· Group 17: Halogens: Very reactive non-metals. Exist as gases (F, Cl), a liquid (Br), and solids (I, At) at room temperature. They are the most reactive non-metals.
· Group 18: Noble Gases: Unreactive (inert) gases. They are stable because they have a full outer shell of electrons.
5. Diagrams
· Table 3.2: A table showing the relationship between group number and the number of valence electrons for Groups 1, 2, 13, 14, 15, 16, 17, and 18.
· Figure 3.14: Atomic Size in Group 1: A diagram of the Group 1 metals (Li, Na, K, Rb, Cs, Fr) with arrows indicating that reactivity, atomic size, and metallic properties increase as you move down the group.
· Figure 3.15: Periodic Table Reactivity Map: A stylised periodic table coloured to show metals, metalloids, and non-metals. Arrows point to the bottom-left, indicating the area where metallic properties, atomic size, and reactivity are highest.
6. Examples
· Group 1 Reactivity: Potassium (K) reacts more violently with water than sodium (Na).
· Halogens: Fluorine (F) and chlorine (Cl) are gases, bromine (Br) is a liquid, and iodine (I) is a solid.
7. Test Tips
· You will be asked to predict the reactivity of an element based on its position. Remember the opposite trends for metals and non-metals.
· Be able to link the group number to valence electrons and the period number to the number of electron shells.
· Know the names and properties of the key groups: Alkali Metals, Halogens, and Noble Gases.
---
Topic 3.3: Common Substances
Learning Intention: Identify types of substances (metallic, ionic, covalent) based on their general properties.
1. Key Concepts
· Elements can bond to form new substances.
· The type of bond formed depends on whether the elements involved are metals or non-metals.
· Pure substances can be classified as metallic, ionic, or covalent based on their bonding and structure.
· Each type of substance has a set of general properties.
2. Definitions
· Chemical Bond: An electrostatic force that connects atoms to one another.
· Chemical Formula: An expression showing the elements in a compound and their ratio, using symbols and numbers (e.g., H₂O, NaCl).
· Compound: A pure substance made of two or more different elements that are chemically joined together in a fixed ratio.
· Metallic: A type of substance made up of metal atoms bonded to other metal atoms.
· Ionic: A type of substance generally made up of metals bonded to non-metals.
· Covalent: A type of substance made up of non-metals bonded to non-metals.
· Crystalline Solid: A solid with a highly ordered, repeating arrangement of particles (atoms, ions, or molecules).
· Giant Network Solid: A continuous network of atoms joined together by covalent bonds (also called a covalent network solid).
3. Explanations
· Types of Chemical Bonds:
1. Metallic Bonding: Occurs between metals (e.g., in a piece of copper wire).
2. Ionic Bonding: Occurs between a metal and a non-metal (e.g., in table salt, NaCl).
3. Covalent Bonding: Occurs between non-metals (e.g., in water, H₂O).
· Using the Periodic Table to Classify: By looking at the elements in a chemical formula and finding them on the periodic table, you can predict the bond type.
· Metallic: The formula will be a single element symbol from the left/middle of the table (e.g., Fe, Ag, Al).
· Ionic: The formula will contain at least one metal (left side) and one non-metal (right side) (e.g., NaCl, CaCO₃).
· Covalent: The formula will contain only non-metals (right side) (e.g., CO₂, H₂O, O₂).
· General Properties of Substances:
· Metallic: High melting/boiling points, good conductors of heat and electricity, malleable (can be hammered into shape), ductile (can be drawn into wires), lustrous (shiny), high density.
· Ionic: High melting/boiling points, conduct electricity only when molten (melted) or dissolved in water (but not as a solid), brittle, form crystalline lattices, high density.
· Covalent: Low melting/boiling points, poor conductors of heat and electricity (good insulators), soft and flexible, often dull, low density.
4. Important Facts to Memorise
· Exceptions to the Rules: Some substances have extreme properties due to their structure. For example, diamond (a covalent substance) has an extremely high melting point (4500°C) because it is a giant network solid with a very strong arrangement of covalent bonds.
· Pure substances can be elements (one type of atom) or compounds (two or more types of atoms joined).
· Metallic substances are usually elemental. Ionic substances are always compounds. Covalent substances can be elemental (e.g., O₂) or compounds (e.g., CO₂).
5. Diagrams
· Figure 3.18: Classification of Pure Substances: A flow chart showing the breakdown.
· Metallic: Elemental -> Crystalline Solid (e.g., Silver).
· Ionic: Compound -> Crystalline Solid (e.g., Calcium Carbonate).
· Covalent: Can be Elemental (e.g., Oxygen gas) or Compound. Compounds can be Discrete Molecules (e.g., Glucose, Carbon Dioxide) or Giant Network Solids (e.g., Silica).
· Table 3.4: A large table comparing the properties (melting/boiling points, electrical conductivity, heat conductivity, brittleness, lustre, density) of metallic, ionic, and covalent substances side-by-side.
6. Examples
· Metallic: Aluminium foil.
· Ionic: Table salt (NaCl), baking soda (NaHCO₃), marble (CaCO₃).
· Covalent: Sugar (C₆H₁₂O₆), oxygen gas (O₂), carbon dioxide (CO₂), plastic, silica (SiO₂) in rocks.
7. Test Tips
· Be able to classify a substance from its chemical formula by identifying the types of elements present.
· Be able to link the type of substance to its general properties. A common question is, "Why is metal used for frying pans?" (Answer: It's a good conductor of heat).
· Remember that ionic substances only conduct electricity when the ions are free to move (molten or dissolved).
---
Topic 3.4: Development of the Periodic Table
Learning Intention: Outline how the modern periodic table was developed and refined over time through a process of review by the scientific community.
1. Key Concepts
· The periodic table is the work of many scientists over hundreds of years.
· Early ideas about elements were based on philosophy (e.g., Aristotle's four elements).
· Over time, scientists used evidence to group elements by their properties and atomic mass.
· The table was refined as new elements were discovered and a better understanding of atomic structure emerged.
2. Definitions
· Chemical Property: A property of a substance that is observed during a chemical reaction (e.g., flammability, reactivity).
· Physical Property: A property of a substance that can be observed and measured without changing its composition (e.g., colour, melting point, density, hardness).
· Dalton's Atomic Theory: The theory proposed by John Dalton that all matter is made up of tiny particles called atoms.
3. Explanations and Timelines
· Ancient Greeks: Philosophers like Aristotle believed all matter was made of four elements: earth, air, fire, and water. This was not based on scientific evidence.
· John Dalton (early 1800s): Produced one of the first tables of 20 elements. He assigned each an atomic mass and a symbol. His atomic masses were later found to be incorrect.
· Johann Döbereiner (1829): Grouped elements with similar physical and chemical properties into sets of three called triads (e.g., Lithium, Sodium, Potassium). This idea of grouping by properties was a foundation for the modern table.
· John Newlands (1864): Arranged the 60 known elements in order of increasing atomic mass. He noticed that every eighth element had similar properties, which he called the Law of Octaves. The pattern didn't hold for all elements (e.g., he grouped iron with oxygen and sulfur).
· Dmitri Mendeleev (1869): Arranged elements in order of increasing atomic mass, but crucially, he also placed them into vertical columns (groups) based on their similar chemical properties. He was a genius because he left gaps in his table for elements that were not yet discovered and boldly predicted their properties. When gallium and germanium were later found, their properties closely matched his predictions.
· Henry Moseley (1913): Discovered that the physical and chemical properties of elements were related to their atomic number (number of protons) , not their atomic mass. He rearranged the table by atomic number, solving some of the issues with Mendeleev's table and creating the basis for the modern periodic table we use today.
4. Important Facts to Memorise
· The modern periodic table is a result of a process of review and contribution by the global scientific community.
· Mendeleev is often called the "father" of the periodic table because of his key insights of grouping by properties and leaving gaps for undiscovered elements.
· Moseley's contribution was critical because arranging by atomic number (rather than atomic mass) provided a more fundamental and accurate organisation.
5. Diagrams
· Figure 3.20: Döbereiner's Triads: An image showing how Döbereiner grouped elements like Li, Na, K and Cl, Br, I together.
· Figure 3.22: Newlands' Arrangement: A diagram showing elements arranged in rows, highlighting his "octaves" concept.
· Figure 3.23: Mendeleev's Table: A depiction of his table with gaps and predictions.
· Figure 3.24: Moseley: A portrait of Henry Moseley.
6. Examples
· Mendeleev left a gap below aluminium (Al) and called the undiscovered element "eka-aluminium". When gallium (Ga) was discovered, its properties matched Mendeleev's predictions almost perfectly.
7. Test Tips
· Be able to place the key scientists (Dalton, Döbereiner, Newlands, Mendeleev, Moseley) in chronological order and state their main contribution.
· Understand why Mendeleev's table was more accepted than Newlands' – because his gaps showed he understood the pattern was predictive, not just descriptive.
· Know the difference between Mendeleev's (atomic mass) and Moseley's (atomic number) organising principles.
---
WHAT TO KNOW FOR TEST:
How to look at periodic table (in red 3.1)
Keywords and definition + subheadings + name of groups and properties (3.2)
Periodic table can be divided into 3 diff groups
Trends in periodic tables
Summary and graphs/tables
Octect rule (3.3)
Three diff types of bondings and their definitions
Electron configuration how to configure(3.5)
How to form ions
How to write ionic formulas
How to write polyatomic ions
You should download this free resource.
But... if you want guaranteed top-quality content, you should also check out ATARNotes+!
1,000+ trusted books, tests, flashcards, videos, exams and text guides.
Browse AllHave some notes you would like to share?
Help other students with your contribution and earn leaderboard points!
We hope this download helps!
But... if you want guaranteed top-quality content, you should also check out ATARNotes+!
1,000+ trusted resources.
Browse All