Science, Atoms, Chemical Reactions and Acids & Bases

1/2 Developing the atomic model • Explain that modern atomic theory was developed over hundreds of years • Describe the atomic models of Democritus and Dalton, Thompson, Rutherford 3 Introduction to Periodic Table • Identify the symbol, name, atomic number and mass number of an element. 5 Bohr's Model of an atom • Draw Bohr models for any of the first 20 elements. • Write the electron configuration for the first 20 elements. 6/7 Isotopes • Define isotope • Identify isotopes from atomic number and mass number • Apply notation conventions to isotopes • Draw Bohr models for each isotope of an element 8 Radioactive Decay • Describe three types of radioactive decay • Define a radioisotope • Complete nuclear decay equations 11 Physical change • Define physical change • Identify examples of physical change – evaporation, condensation, freezing, melting, dissolving and sublimation • Recognise four basic states – solid, liquid, gas, aqueous (and symbols used to represent them) 2 Chemical/Physical change Consolidation • Identify elements present and number of atoms in chemical formulae • Match word equations with chemical formula equations • Recognise that atoms forming molecules are connected by chemical bonds 3 Exothermic and endothermic reactions • Recall that chemical bonds connect atoms in molecules and compounds • Classify reactions as exothermic or endothermic 5 Law of conservation of mass • Identify reactants and products in word and chemical formula equations 6 Balancing Equations • Balance chemical equations 7 Neutralisation • Identify the reactants and products of neutralisation • Explore the applications of neutralisation in everyday life - antacids 9 Acid + metal reactions • Identify the reactants and products of acid-metal reactions • Compare acid metal reactions with neutralisation reactions • Predict the products of the reactions given the reactants 11 Chemical reactions - acid + carbonate • Describe the methods to test for the presence of specific gases • Predict the reactants of a chemical reaction when given the products or vice versa 17 Chemical reactions - combustion #1 • Identify reactants and products of combustion reactions • -Identify the difference between combustion of metals and non-metals 18/19 Chemical reactions - respiration and photosynthesis • Identify the reactants and products of respiration and photosynthesis • Identify where and when these reactions occur

1/2 Developing the atomic model

 Who first proposed that matter is made up of indivisible particles called atoms?

Democritus —-- (Chemist John Dalton introduced the atomic theory in the early 19th century.)

What did John Dalton contribute to atomic theory?

He proposed that atoms of the same element are identical and combine in whole-number ratios to form compounds. —- (John Dalton formulated the atomic theory, proposing that all matter is composed of atoms, which are indivisible and combine in specific ratios to form compounds.)

What did J.J. Thomson discover about the atom?

He discovered the electron and proposed the “plum pudding” model. —- (J.J. Thomson discovered the electron, demonstrating that atoms are not indivisible and contain smaller charged particles.)

How did Rutherford’s model change our understanding of the atom?

He discovered the nucleus and proposed that electrons orbit around it. —- (Rutherford's model introduced the idea of a small, dense nucleus at the centre of the atom, surrounded by orbiting electrons, leading to the understanding that most of an atom's volume is empty space.)

How was modern atomic theory developed?

It was developed over hundreds of years through the contributions of many scientists. —-(While John Dalton is credited for proposing modern atomic theory. Dalton built his theory upon laws previously identified by Lavoisier and Proust as a basis for his atomic theory: Law of Multiple Proportions.)

3 Introduction to the Periodic Table

What information does each element’s box on the periodic table show?

The symbol, name, atomic number, and mass number. —-(The box on the periodic table for each element contains essential information that helps in understanding the element's properties and behaviour. Here's a summary of what each box typically shows:

• Atomic Number: The number of protons in the nucleus, which determines the element's identity.

• Elemental Symbol: A one or two-letter abbreviation representing the element.

• Atomic Mass: The average mass of the element's isotopes, which provides a rough estimate of the element's mass.

• Name: The full name of the element, which is derived from its atomic structure and properties.

• Electron Configuration: The arrangement of electrons in the atom's orbitals, which is crucial for understanding chemical behaviour.)

What does the atomic number represent?

The number of protons in an atom. —-(The atomic number represents the number of protons in the nucleus of an atom, which uniquely identifies the element and determines its position in the periodic table.)

What does the mass number represent?

The total number of protons and neutrons in an atom. —-(The mass number represents the total number of protons and neutrons in the nucleus of an atom, indicating its isotopic identity.)

5 Bohr’s Model of an Atom

Q9: What does a Bohr model show?

Electrons orbiting the nucleus in specific energy levels. —-(The Bohr model illustrates the structure of an atom, depicting electrons orbiting a central nucleus in defined energy levels, and explains the quantized nature of atomic energy levels.)

How many electrons can the first energy level hold?

2

How many electrons can the second energy level hold?

8

What is the electron configuration for oxygen (atomic number 8)?

2,6 

What is an isotope?

Atoms of the same element with different numbers of neutrons. —-(An isotope is a variant of a chemical element that has the same number of protons but a different number of neutrons in its nucleus, resulting in different atomic masses.)

How do you identify isotopes using atomic and mass numbers?

Isotopes have the same atomic number but different mass numbers.—-(Isotopes of an element have the same atomic number but different mass numbers, allowing them to be identified by the number of neutrons in the nucleus.)

What notation convention is used for isotopes?

Element name followed by mass number (e.g., Carbon-14 or ¹⁴₆C). —-(Isotopes are identified using a notation that includes the chemical symbol, atomic number, and mass number, allowing clear differentiation between isotopes of the same element.)

8 Radioactive Decay

What are the three main types of radioactive decay?

Alpha, beta, and gamma decay.

What is a radioisotope?

An isotope with an unstable nucleus that emits radiation. —-(A radioisotope is an unstable isotope of an element that emits radiation as it decays into a more stable form.)

What happens during alpha decay?

The atom emits an alpha particle (2 protons and 2 neutrons).—-(During alpha decay, an unstable nucleus emits an alpha particle, which consists of 2 protons and 2 neutrons, resulting in the formation of a new element with lower mass and atomic number.)

11 Physical Change

What is a physical change?

A change in state or form where no new substance is formed. —-(During alpha decay, an unstable nucleus emits an alpha particle, which consists of 2 protons and 2 neutrons, resulting in the formation of a new element with lower mass and atomic number.)

Give three examples of physical changes.

Melting, freezing, and dissolving.

What are the four basic states of matter and their symbols?

Solid (s), liquid (l), gas (g), aqueous (aq).

2 Chemical/Physical Change Consolidation

How can you find the number of atoms in a chemical formula?

By looking at the figure/symbol next to each element. —-(To determine the number of atoms in a chemical formula, identify the symbols for each element and count the atoms based on the subscripts in the formula.)

What connects atoms in a molecule?

Chemical bonds.

3 Exothermic and Endothermic Reactions

What is an exothermic reaction?

A reaction that releases energy (usually heat). —--(An exothermic reaction is a chemical reaction that releases energy to its surroundings, usually in the form of heat, light, or sound.)

What is an endothermic reaction?

A reaction that absorbs energy. —-(An endothermic reaction is a chemical reaction that absorbs heat from its surroundings, resulting in a positive enthalpy change (ΔH > 0) and often causing the surrounding environment to feel cooler.)

5 Law of Conservation of Mass

What does the law of conservation of mass state?

Mass is neither created nor destroyed in a chemical reaction. —-(The law of conservation of mass states that mass cannot be created or destroyed in an isolated system during a chemical reaction or physical process.)

What are reactants and products?

Reactants are starting substances; products are formed after the reaction. —-(In a chemical reaction, reactants are the substances that start the reaction, while products are the substances formed as a result of the reaction.)

6 Balancing Equations

Why must chemical equations be balanced?

To ensure the same number of each type of atom appears on both sides of the equation.

7 Neutralisation

What type of reaction is neutralisation?

A reaction between an acid and a base forming salt and water.

What are antacids used for?

To neutralise excess stomach acid.

9 Acid + Metal Reactions

What are the products of an acid–metal reaction?

A salt and hydrogen gas.

How are acid–metal reactions similar to neutralisation reactions?

Both produce a salt as one of the products.

11 Chemical Reactions – Acid + Carbonate

What are the products of an acid–carbonate reaction?

A salt, water, and carbon dioxide.

How can you test for carbon dioxide?

Bubble the gas through limewater; it turns milky.

17 Chemical Reactions – Combustion

What are the products of combustion reactions?

Carbon dioxide and water (for hydrocarbons).

How does combustion of metals differ from non-metals?

Metals form metal oxides; non-metals form non-metal oxides.

18/19 Respiration and Photosynthesis

What are the reactants and products of respiration?

Reactants: glucose and oxygen; Products: carbon dioxide, water, and energy.

What are the reactants and products of photosynthesis?

Reactants: carbon dioxide and water; Products: glucose and oxygen

Q39: Where does photosynthesis occur?

In plant cells, in the chloroplasts.

Where does respiration occur?

In all living cells, in the mitochondria.