Science Lecture Notes: Chemistry, Physics, and Biology Review

Comprehensive vocabulary flashcards covering atomic structure, chemical reactions, physical forces and motion, evolutionary biology, and stellar astronomy based on the lecture notes provided lecture materials.

Element

A substance made up of atoms that all have the same number of protons.

Atoms in a pinhead

There are approximately $8,000,000$ atoms found in this small space.

Proton

A positively charged particle found in the nucleus of an atom.

Neutron

A particle with no charge found in the nucleus of an atom.

Electron

A negatively charged particle found whizzing around the nucleus of an atom.

Atomic Number

The number of protons an atom has, which determines the specific element.

Mass Number

The total number of protons plus the number of neutrons in an atom's nucleus.

Formula for Neutrons

The calculation represented by $A - Z$, where $A$ is the mass number and $Z$ is the atomic number.

Isotopes

Atoms of an element that have the same atomic number but a different mass number due to a different number of neutrons.

Electron Configuration (First 20 elements)

The arrangement of electrons in shells drawn in the configuration $2 - 8 - 8 - 2$.

Ion

An atom that has become charged because an electron was removed or added.

Cation

A positively charged ion formed when an atom loses electrons.

Anion

A negatively charged ion formed when an atom gains electrons and follows the naming convention of adding the suffix '-ide'.

Ionic Bonding

A chemical bond involving the electrostatic attraction of two oppositely charged ions seeking full outer shells.

Polyatomic Ion

A group of two or more atoms that behave as a single unit and carry a charge.

Reactivity

A substance's tendency to chemically interact with other substances.

Group 1 Reactivity

Reactivity that increases towards the bottom of the group because the single valence electron becomes further from the nucleus (increased atomic radius).

Group 8 Reactivity

Elements in this group are not reactive at all due to having a full valence shell.

Law of Conservation of Matter

The principle stating that matter cannot be created or destroyed, only change forms, requiring chemical equations to be balanced.

Coefficient

The number of molecules of a compound in a chemical equation that can be changed during balancing.

Acid

A substance that is sour, produces a burning sensation, and releases hydrogen ions ($H^+$) in water.

Base

A substance that is bitter, slippery to touch, and releases hydroxide ($OH^-$) ions when dissolved in water (alkalis).

pH Scale

A scale describing relative acidity or alkalinity where Acid is less than $7$, Neutral is $7$, and Base is greater than $7$.

Indicator

Substances like litmus paper or universal indicator that change colour to reveal if an unknown substance is acidic or basic.

Acid + Metal Carbonate Reaction

A reaction that produces a salt, water, and carbon dioxide.

Combustion

The reaction of burning which requires a fuel source (usually hydrocarbons) and oxygen.

Complete Combustion

A reaction occurring with unlimited oxygen that produces carbon dioxide and water ($CO_2 + H_2O$).

Reaction Rate

The speed at which a reaction naturally occurs; can be increased by factors like temperature, concentration, and surface area.

Catalyst

Chemicals that speed up reactions but are not used up in the reaction itself.

Collision Theory

The theory that particles must collide in the correct orientation and with enough energy for a reaction to occur.

Systematic Error

An error that can be identified by repeating an experiment with different equipment or comparing to a known result.

Variation

Differences in traits across or within species caused by genetic differences that can be inherited.

Mutation

A change to a DNA sequence that results in a different protein being made, leading to variations in alleles.

Adaptation

The process of adjusting behaviour, physiology, or structure to become better suited to an environment.

Natural Selection

The process where organisms better adapted to their environment have a greater chance of survival and passing on traits (survival of the fittest).

Evolution

The change of characteristics over several generations due to natural selection.

Speciation

The formation of a new species comprising organisms capable of breeding to produce viable and fertile offspring.

Divergent Evolution

Evolution where physically separated populations of the same species face different selection pressures and evolve separately.

Homologous Structures

Physical features in different species that exhibit a similar pattern but serve different functions, indicating a shared common ancestor.

Convergent Evolution

Evolution where different species develop similar structures (like wings on birds and butterflies) because they face similar selection pressures.

Analogous Structures

Similar structures that perform the same function but are structurally different, suggesting no recent common ancestor (e.g., dolphin and shark bodies).

Artificial Selection/Selective Breeding

The evolution of organisms caused by human interference, such as selecting desirable traits in dogs or crops.

Speed

The distance travelled by an object per unit time, calculated as $v = \frac{d}{t}$ and measured in $m/s$.

Acceleration

A measure of how quickly speed is changing, calculated as $a = \frac{v_f - v_i}{t}$ and measured in $m/s^2$.

Mass

A measure of how much matter is in an object, measured in kilograms ($kg$), which does not change based on location.

Weight

The force 'pulling down' on an object, calculated as $W = mg$ and measured in Newtons ($N$).

Inertia

The tendency of objects to resist changes in their state of motion, described by Newton's First Law.

Newton's Second Law of Motion

The law stating that acceleration is produced when a force acts on a mass, expressed as $F = ma$.

Nuclear Fusion

The process inside stars where atoms collide and fuse together (e.g., hydrogen to helium) at temperatures of millions of degrees.

White Dwarf

The leftover core of an average star, described as a dead star that takes millions of years to fade away.

Supernova

A huge explosion occurring when the core of a massive star collapses.

Frequency

The number of complete waves that pass a point in one second, measured in Hertz ($Hz$).

Transverse Wave

A type of wave where the disturbance is perpendicular to the direction of propagation, such as electromagnetic waves.

Longitudinal Wave

A type of wave where the disturbance is parallel to the direction of propagation, such as sound.

Absolute Magnitude

A scale ( -10 to +10) for measuring the actual brightness of a star as if it were placed $33$ light years from Earth.

Spectroscopy

The study of light from an object using a spectrometer to determine its chemical makeup based on emitted wavelengths.