eooy gemni notes year 9

Parts of an Atom

An atom consists of protons, neutrons, and electrons, with protons and neutrons in the nucleus and electrons in shells.

Proton Charge and Mass

Protons have a relative charge of +1 and a relative mass of 1.

Neutron Charge and Mass

Neutrons have a relative charge of 0 and a relative mass of 1.

Electron Charge and Mass

Electrons have a relative charge of -1 and a negligible relative mass of approximately 1/1840.

Overall Charge of Atoms

Atoms have no overall electrical charge due to an equal number of protons and electrons.

John Dalton's Atomic Model

Introduced the idea of atoms as solid, indivisible spheres in 1803.

Plum Pudding Model

Proposed by J.J. Thomson in 1897, depicting the atom as a sphere of positive charge with negative electrons scattered within.

Gold Foil Experiment

Conducted by Ernest Rutherford in 1911, concluded that the atom has a small, dense nucleus surrounded by mostly empty space.

Niels Bohr's Model

Refined the atomic model by stating electrons orbit the nucleus in fixed energy levels (shells) in 1913.

Isotopes

Atoms of the same element with the same number of protons but different numbers of neutrons.

Relative Atomic Mass (Ar)

The average mass of an atom of an element compared to 1/12th the mass of a carbon-12 atom.

Cations and Anions

Cations are positive ions formed when atoms lose electrons, while anions are negative ions formed when atoms gain electrons.

Shell Capacities

The first shell can hold 2 electrons, the second can hold 8, and the third can hold 8 (for the first 20 elements).

Word Equations

Show the names of reactants on the left and products on the right, separated by an arrow.

Balanced Symbol Equations

Represent chemical reactions with formulas showing the same number of atoms for each element on both sides.

State Symbols

Indicate the physical state of substances in equations: (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous.

Filtration

A physical method used to separate an insoluble solid from a liquid.

Crystallisation

Technique to separate a soluble solid from a solvent by evaporation.

Simple Distillation

A method to separate a liquid solvent from a dissolved solid by heating.

Fractional Distillation

Separates a mixture of miscible liquids based on different boiling points.

Paper Chromatography

Technique to separate mixtures of soluble substances based on their solubility.

Early Classifications of Elements

Elements were sorted by atomic weight, leading to incorrect groupings.

Law of Octaves

Proposed by John Newlands, stating similar properties recur every eighth element based on atomic weight.

Mendeleev's Periodic Table

Arranged elements by atomic weight while predicting properties of undiscovered elements.

Modern Periodic Table

Arranged by increasing atomic number, resolving inconsistencies in Mendeleev's table.

Groups in the Periodic Table

Vertical columns indicate how many electrons are in an atom's outer shell.

Periods in the Periodic Table

Horizontal rows show the number of electron shells an atom has.

Group 1 Elements (Alkali Metals)

Highly reactive metals with one electron in their outer shell, react vigorously with water.

Group 7 Elements (Halogens)

Non-metals with seven electrons in their outer shell, exist as diatomic molecules.

Group 1 Reactivity Trend

Reactivity increases down the group due to the outer electron being further from the nucleus.

Group 7 Reactivity Trend

Reactivity decreases down the group as atomic radius and shielding increase.

Transition Metals

Metals in the center of the periodic table with higher melting points and less reactivity.

States of Matter

Solids have fixed shape and volume; liquids flow; gases fill their container.

Octet Rule

Atoms react to achieve a full outer shell of electrons, resembling noble gas configurations.

Ionic Bonding

The electrostatic attraction between positively charged metal ions and negatively charged non-metal ions.

Giant Ionic Lattice

Ions arranged in a repeating 3D structure with strong electrostatic bonds.

Covalent Bonding

Occurs when non-metal atoms share electron pairs to fill outer shells.

Simple Molecular Substances

Composed of small molecules with strong covalent bonds inside and weak forces between them.

Graphene

A 2D layer of carbon arranged in a honeycomb lattice, known for its strength and electrical conductivity.

Fullerenes

Carbon molecules with hollow shapes; examples include Buckminsterfullerene and carbon nanotubes.

Metallic Structure

A giant lattice of positive metal ions surrounded by delocalized electrons.

Nanotechnology

Deals with particles from 1 to 100 nanometers in size, with unique properties.

Surface Area to Volume Ratio

Smaller particles have a higher ratio, leading to increased reactivity.

Oxidation Reactions

Form metal oxides when metals react with oxygen.

Reduction Reactions

Involves the removal of oxygen from compounds.

Reactivity Series

Arranges metals based on how easily they lose electrons to form positive ions.

Displacement Reaction

Occurs when a more reactive metal displaces a less reactive metal from its compound.

Extraction of Metals with Carbon

Metals below carbon in the reactivity series can be extracted by heating with carbon.

Electrolysis

Used to extract metals above carbon in the reactivity series.

Genetic Variation

Differences in characteristics between individuals driven by genetic factors.

Environmental Variation

Differences caused by external conditions affecting organisms throughout their life.

Continuous Variation

Characteristics controlled by multiple genes and influenced by the environment, such as height.

Discontinuous Variation

Characteristics that fall into distinct categories, controlled by a single gene.

Natural Selection

The process where individuals with advantageous traits survive and reproduce, leading to evolution.

Antibiotic Resistance Development

Occurs when bacteria evolve to survive exposure to antibiotics, often due to mutations.

Fossil Formation

Preserved remains of organisms formed through various processes, often found in sedimentary rock.

Extinction Causes

Permanent disappearance of a species due to environmental changes, predation, or competition.

The Linnaean System

A classification system categorizing organisms based on physical structures.

Binomial Nomenclature

Two-part naming system for organisms, including genus and species names.

Three-Domain System

Divides life into Archaea, Bacteria, and Eukaryota based on genetic analysis.

Carbohydrates

Biological molecules providing energy, including monosaccharides and polysaccharides.

Proteins

Essential for growth and repair, composed of amino acids.

Lipids

Molecules for long-term energy storage and insulation, consisting of glycerol and fatty acids.

Enzymes Definition

Biological catalysts that speed up chemical reactions without being consumed.

Mechanism of Enzymes

Substrates bind to the active site of an enzyme, forming an enzyme-substrate complex.

Factors Affecting Enzymes

Temperature and pH can influence enzyme activity leading to denaturation.

Amylase Practical Method

Investigate the effect of pH on the breakdown of starch using Benedict's solution.

Tests for Reducing Sugars

Use Benedict’s solution to test for glucose presence.

Test for Starch

Add Iodine solution to determine starch presence.

Test for Proteins

Use Biuret solution to check for protein presence.

Test for Lipids

Perform emulsion test using ethanol and distilled water.

Eukaryotic Cells

Complex cells with a nucleus; include animal and plant cells.

Animal Cell Structures

Include nucleus, cytoplasm, cell membrane, mitochondria, and ribosomes.

Plant Cell Structures

Includes all animal cell structures plus cell wall, vacuole, and chloroplasts.

Microscopy Definitions

Magnification and resolution are vital for examining cells.

Light vs. Electron Microscopes

Light microscopes are cheaper and can view live cells; electron microscopes offer higher resolution but examine dead specimens.

Prokaryotic Cells

Simpler cells lacking a nucleus; DNA floats in cytoplasm.

Diffusion

Passive movement of particles from high to low concentration.

Osmosis

Net movement of water across a selectively permeable membrane.

Active Transport

Movement of substances against a concentration gradient, requiring energy.

Chromosomes Definition

Coiled DNA molecules carrying genes.

Mitosis

Process of cell division producing genetically identical daughter cells.

Stages of Mitosis

Include interphase, mitosis, and cytokinesis.

Energy Stores

Different ways energy is stored in various forms, like thermal and kinetic.

Power Definition

Rate of energy transfer or work done; measured in Watts.

Efficiency Calculation

Efficiency = (Useful output energy / Total input energy) × 100.

Renewable Resources

Energy sources that replenish naturally, like solar and wind.

Non-Renewable Resources

Finite resources that take millions of years to form, like fossil fuels.

Fossil Fuel Power Stations

Generate electricity by burning fuel to produce steam that turns turbines.

Transverse Waves

Waves where vibrations occur perpendicular to the direction of travel.

Longitudinal Waves

Waves where vibrations occur parallel to the direction of travel.

Wave Properties

Includes amplitude, wavelength, frequency, and period.

Law of Reflection

Angle of incidence equals angle of reflection.

Refraction Definition

Change in direction of a wave when entering a different medium.

Dispersion Definition

The separation of light into its component colors.

Diffraction Definition

Spreading out of waves after passing through a gap.

Electromagnetic Spectrum Order

Includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays.

Properties of Electromagnetic Waves

Transverse waves traveling at the speed of light, with increasing energy as frequency increases.

Seismic Waves

Waves generated by earthquakes, including P-waves and S-waves.

Convex Lenses

Thicker in the middle, refracting light to a point called the principal focus.