Atoms

Unit Review Sheet

Facts and Definitions

Lesson 1: Invisible Matter

• indivisible: not capable of being separated into parts
• atom: the smallest portion into which an element can be divided and still retain its properties
• element: a substance that cannot be broken down into a simpler one
• structure: a system or organization made up of related parts functioning as a whole
• function: an action or use for which something is designed
• property: a characteristic, quality, or distinctive feature of something
• system: a combination of related parts organized into a whole
• matter: a substance or material of a particular kind that has mass, occupies space, and is convertible to energy

Lesson 2: Atomic Structure

• atomic model: a representation of the structure of an atom
• nucleus: the positively charged central region of an atom, consisting of protons and neutrons and containing most of the mass of the atom
• electron: a negatively charged particle with a small mass that is found in all matter; orbits the nucleus of an atom
• neutron: a neutral particle with a mass approximately equal to that of a proton
• neutral: having no charge
• proton: a particle that is a component of all atomic nuclei and carries a positive charge equal to that of the electron's negative charge

Lesson 3: Properties of Matter I

• conductivity: the ability of an object or substance to transmit heat, electricity, or sound
• ductile: able to be drawn out into wire or hammered into very thin sheets
• electrical: involving the conduction of electric current
• luster: a bright and shiny condition or tone
• malleable: describes a substance that can be shaped or bent without breaking
• metal: a chemical element that is malleable and ductile, usually solid, has luster, and is a good conductor of heat and electricity
• nonmetal: elements that do not have the character of metals; they can be gases such as carbon or nitrogen
• patterns: observed arrangements of forms and events that are used for organization and classification
• periodic table: display of the chemical elements organized on the basis of their atomic numbers, electron configurations, and recurring chemical properties
• thermal: relating to, affected by, or producing heat

Lesson 4: Solid, Liquid, Gas: What's the Difference?

• atmospheric pressure: the downward pressure exerted by the weight of the atmosphere
• solid: a material that keeps its shape and resists change in shape at room temperature and normal atmospheric pressure
• liquid: a substance that flows, that is a fluid at room temperature and normal atmospheric pressure, and whose shape can be changed
• gas: a substance that is neither a solid nor a liquid at ordinary temperatures and has the ability to expand
• state of matter: a state in which matter can exist, depending on temperature and pressure (the states are solid, liquid, gaseous, and plasmatic)
• plasma: a gas made up of ions and electrons; found primarily in the Sun and stars
• melting point: the temperature at which a substance changes from a solid to a liquid
• boiling point: the temperature at which a heated liquid turns to gas

Lesson 5: Properties of Matter II

• density: a measure of the mass per unit volume of matter
• solubility: the extent to which one substance is able to dissolve in another
• volume: the size of a three-dimensional space enclosed within or occupied by an object
• mass: a measure of the amount of matter an object contains
• weight: a measure of the heaviness of an object as a result of the influence of gravity

Lesson 6: The Recurring (Periodic) Table of Elements

• atomic mass: the mass of an atom
• electron configuration: the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals
• metalloid: a nonmetallic element that has properties between those of a metal and nonmetal; some are also called semiconductors

Lesson 7: Classifying Matter

• compounds: substances formed by the chemical combination of elements in fixed proportions; pure chemical compounds can be separated into simpler substances by chemical reactions
• chemistry: a branch of science dealing with the structure, composition, properties, and reactive characteristics of substances, especially at the atomic and molecular levels
• fixed proportions: unchanging quantities of each element that are part of a compound
• mixtures: a combination of two or more substances that are not chemically united and do not exist in fixed proportions to each other

Lesson 8: Final Project

• [none]