MYP 4 Science End of Year Examination Review

Vocabulary-style flashcards covering the key concepts for the MYP 4 Science End of Year examination, spanning chemistry, physics, and biology topics.

Dalton's Hypothesis

The scientific theory proposing that all matter is composed of small, indivisible particles called atoms, and that all atoms of a given element are identical in mass and properties.

Cathode Rays

Streams of electrons observed in vacuum tubes that travel from the negatively charged electrode to the positively charged electrode.

Electron

A subatomic particle that carries a negative electric charge, discovered through the study of cathode rays.

Nucleus

The small, dense, positively charged central core of an atom, containing protons and neutrons.

Rutherford's Experiment

The gold foil experiment which demonstrated that atoms consist of a tiny, massive, positive nucleus surrounded by mostly empty space.

Plum-Pudding Model

An early model of the atom proposed by J.J. Thomson where negatively charged electrons were embedded within a uniform sphere of positive charge.

Planetary Model

The atomic model where electrons move in circular orbits around a central nucleus, similar to planets orbiting the sun.

Proton

A subatomic particle located in the nucleus with a positive charge of $+1$ and a relative mass of $1$.

Neutron

A subatomic particle found in the nucleus with no electric charge and a relative mass of $1$, contributing to the atom's mass number.

Atomic Number

The total number of protons found in the nucleus of an atom, which uniquely identifies a chemical element.

Mass Number

The total count of protons and neutrons in an atom's nucleus.

Isotopes

Atoms of the same element that possess the same number of protons but different numbers of neutrons, resulting in different mass numbers.

Ions

Atoms or groups of atoms that have lost or gained electrons, resulting in a net positive or negative electrical charge.

Groups

The vertical columns of the Periodic Table containing elements with similar chemical properties and the same number of valence electrons.

Periods

The horizontal rows of the Periodic Table that indicate the number of electron shells an atom possesses.

Valence Electrons

The electrons located in the outermost shell of an atom that determine its chemical reactivity and bonding behavior.

Ionic Bond

A chemical bond formed by the electrostatic attraction between oppositely charged ions, usually involving the transfer of electrons from a metal to a non-metal.

Covalent Bond

A chemical bond that involves the sharing of electron pairs between atoms, typically occurring between non-metal atoms.

Metallic Bond

The type of chemical bonding that results from the attraction between metal cations and a surrounding sea of delocalized valence electrons.

Lewis Dot Structure

A diagrammatic representation of an atom or molecule that shows the valence electrons as dots around the chemical symbol.

Molecules

Neutral groups of two or more atoms held together by covalent chemical bonds.

Solutions

Homogeneous mixtures composed of two or more substances where a solute is fully dissolved in a solvent.

Suspensions

Heterogeneous mixtures containing large solid particles that are sufficiently large for sedimentation and will eventually settle out.

pH

A logarithmic scale used to specify the acidity or basicity of an aqueous solution, commonly ranging from $0$ to $14$.

Acids

Substances that release hydrogen ions ($H^+$) in water, typically having a pH less than $7$ and a sour taste.

Bases

Substances that release hydroxide ions ($OH^-$) or accept protons in water, typically having a pH greater than $7$.

Salts

Ionic compounds produced by the neutralization reaction between an acid and a base.

Digestive System

The biological organ system responsible for breaking down food into nutrients, absorbing them into the bloodstream, and eliminating waste.

Classification of Biological Organisms

The process of grouping living things based on shared characteristics; it includes traditional morphological methods and modern genetic/phylogenetic approaches.

Structural Units of Biological Organisms

The fundamental building blocks of life, ranging from cells to tissues, organs, and organ systems.

Photosynthesis

The process by which green plants and some organisms use sunlight to synthesize food from carbon dioxide and water ($6CO_2 + 6H_2O \rightarrow C_6H_{12}O_6 + 6O_2$).

Cellular Respiration

The metabolic process in which cells break down glucose and oxygen to produce energy in the form of $ATP$, releasing carbon dioxide and water as byproducts.

Balancing Chemical Reactions

The process of ensuring that the number of atoms of each element is equal on both the reactant and product sides of a chemical equation to satisfy the law of conservation of mass.