Chemistry Unit Review Flashcards

Questions and Answers

What is an atom?

The number of protons in an atom

The smallest unit of matter (correct)

A substance that cannot be broken down

Negatively charged particles

What is an element?

A substance that cannot be broken down into simpler substances by ordinary chemical means

How is an element represented?

A symbol that consists of either 1 or 2 letters (the first is always capitalized; if there's a second, it's always lowercase)

What is atomic mass?

The number of protons and neutrons in an atom Signup and view all the answers

What is atomic number?

The number of protons in an atom Signup and view all the answers

What is a proton?

Positively charged particles in an atom Signup and view all the answers

What is a neutron?

Particles in an atom with no charge Signup and view all the answers

What is an electron?

Negatively charged particles in an atom Signup and view all the answers

What is the nucleus?

Contains protons and neutrons Signup and view all the answers

What are valence electrons?

Electrons involved in bonding Signup and view all the answers

What is the valence shell?

The outermost energy level of an atom Signup and view all the answers

What is reactivity?

How likely an atom is to bond with another atom Signup and view all the answers

What is the magic number?

Every atom (except hydrogen and helium) wants 8 electrons in its valence shell Signup and view all the answers

Why do atoms (except hydrogen and helium) want 8 electrons in their valence shell?

To feel stable like a noble gas Signup and view all the answers

What is a noble gas?

An element that is naturally stable and will not bond with other elements/has no reactivity Signup and view all the answers

What is a periodic table?

A chart containing all elements organized by atomic number and atomic mass Signup and view all the answers

What is a group/family in the periodic table?

A vertical column Signup and view all the answers

What is a period in the periodic table?

A horizontal row Signup and view all the answers

What is an isotope?

An atom with a different number of neutrons than what the periodic table says Signup and view all the answers

What is an ion?

An atom with a charge because it has either gained or lost electrons Signup and view all the answers

What is an ionic bond?

A bond between a metal and a nonmetal where valence electrons are transferred Signup and view all the answers

What is a covalent bond?

A bond between two nonmetals where valence electrons are shared Signup and view all the answers

What is a metal?

An element that loses electrons during ionic bonding Signup and view all the answers

What is a nonmetal?

An element that gains electrons during ionic bonding Signup and view all the answers

What is conductivity?

The ability of a substance to conduct electricity Signup and view all the answers

What is a compound?

A substance formed when two or more elements chemically combine Signup and view all the answers

What type of compound has high conductivity?

Ionic compound Signup and view all the answers

What type of compound has low conductivity?

Covalent compound Signup and view all the answers

What is a Lewis dot diagram?

A visual representation of an element using its chemical symbol and a dot representing each of its valence electrons Signup and view all the answers

What is the law of conservation of mass?

States that atoms cannot be created or destroyed, only rearranged Signup and view all the answers

What is a chemical formula?

A representation of a chemical compound consisting of the chemical symbols and the number of each element in the compound Signup and view all the answers

What is a chemical equation?

A representation of a chemical reaction written like a math problem Signup and view all the answers

What are reactants?

The substances found before a chemical reaction takes place Signup and view all the answers

What are products?

The substances found after a chemical reaction takes place Signup and view all the answers

What is a physical change?

A change where the atomic structure of a substance stays the same throughout Signup and view all the answers

What are examples of physical changes?

Changing states of matter (ice melting) or ripping paper Signup and view all the answers

What is a chemical change?

A change where the atomic structure of a substance changes Signup and view all the answers

What are examples of chemical changes?

Wood burning and iron rusting Signup and view all the answers

What are ways to speed up a chemical reaction?

Increase surface area Signup and view all the answers

What are ways to tell if a chemical reaction has occurred?

A precipitate forms Signup and view all the answers

What is a catalyst?

A substance that speeds up a chemical reaction Signup and view all the answers

What is a precipitate?

A solid formed when two liquids chemically combine Signup and view all the answers

What is an endothermic reaction?

A chemical reaction in which heat is absorbed, so the surrounding temperature decreases Signup and view all the answers

What is an exothermic reaction?

A chemical reaction in which heat is released, so the surrounding temperature increases Signup and view all the answers

What is a physical property?

A property that can be observed without changing a substance Signup and view all the answers

What is luster?

How shiny or dull a substance is Signup and view all the answers

What is malleability?

The ability of a substance to bend instead of break Signup and view all the answers

What is a chemical property?

A property that can only be observed by changing the chemical makeup of a substance Signup and view all the answers

What is pH?

Whether a substance is an acid or a base Signup and view all the answers

What is a characteristic property?

A property that stays constant no matter how much of the substance is present Signup and view all the answers

What is density?

The relationship between a substance's mass and volume Signup and view all the answers

What is the formula for density?

D = m/v Signup and view all the answers

What is a mixture?

Formed when two or more substances are physically combined Signup and view all the answers

What is a heterogeneous mixture?

A mixture in which individual substances can be seen Signup and view all the answers

What is a homogeneous mixture?

A mixture in which all of the mixture looks the same Signup and view all the answers

What type of change takes place when a compound is formed?

Chemical change Signup and view all the answers

What type of change takes place when a mixture is formed?

Physical change Signup and view all the answers

What is filtering?

A means of separating a solid from a liquid Signup and view all the answers

What is sifting?

A means of separating two different sized solids Signup and view all the answers

What is evaporation?

A means of separating a homogeneous mixture Signup and view all the answers

What is a solution?

Another term for a homogeneous mixture Signup and view all the answers

Study Notes

Fundamental Concepts of Chemistry

Atom: The smallest unit of matter, fundamental building block of all substances.
Element: A pure substance that cannot be decomposed into simpler substances through ordinary chemical reactions.
Chemical Symbol: Represents an element, consisting of one or two letters; the first letter is capitalized, while any second letter is lowercase.

Atomic Structure

Atomic Mass: The combined number of protons and neutrons within an atom.
Atomic Number: Represents the number of protons in an atom's nucleus, unique for each element.
Protons: Positively charged particles found in an atom's nucleus.
Neutrons: Neutral particles that contribute to the mass of an atom, located in the nucleus.
Electrons: Negatively charged particles that orbit the nucleus of an atom.

Chemical Bonding

Valence Electrons: Electrons in the outermost energy level of an atom involved in forming bonds.
Valence Shell: The outermost energy level of an atom where valence electrons reside.
Reactivity: Indicates an atom's tendency to bond with others; influenced by its valence electrons.
Magic Number: Generally refers to an atom's desire for 8 electrons in its valence shell (except hydrogen and helium) for stability.

Periodic Table

Noble Gas: Stable elements that do not readily form bonds due to full valence shells.
Periodic Table: A systematic arrangement of elements by increasing atomic number and atomic mass.
Groups/Families: Vertical columns in the periodic table indicating elements with similar properties.
Periods: Horizontal rows in the periodic table representing elements with increasing atomic number.

Isotopes and Ions

Isotope: Variants of a single element that differ in neutron number, resulting in different atomic masses.
Ion: An atom or molecule that carries a charge due to the loss or gain of one or more electrons.

Types of Chemical Bonds

Ionic Bond: Forms between metals and nonmetals where valence electrons are transferred.
Covalent Bond: Occurs between nonmetals where valence electrons are shared.

Substances and Properties

Conductivity: The ability of a substance to conduct electricity, often high in ionic compounds.
Compound: A substance resulting from the chemical combination of two or more elements.
Ionic Compound: Typically has high conductivity due to free-moving ions.
Covalent Compound: Generally exhibits low conductivity because electrons are shared.

Chemical Change and Reactions

Law of Conservation of Mass: States that mass is neither created nor destroyed during a chemical reaction.
Reactants: Substances present before a chemical reaction occurs.
Products: Substances formed as a result of a chemical reaction.
Chemical Change: Alters the atomic structure of a substance; includes processes like combustion and rusting.

Physical and Chemical Properties

Physical Change: A change where the atomic structure remains unchanged (e.g., melting ice).
Chemical Property: A characteristic that becomes evident during a chemical reaction.
Luster: Describes the shine of a substance.
Malleability: The ability of a substance to deform without breaking.

Mixtures and Separation Techniques

Mixture: A physical combination of two or more substances; can be homogeneous or heterogeneous.
Heterogeneous Mixture: Individual components are distinguishable (e.g., salad).
Homogeneous Mixture: Components are uniformly distributed, appearing as a single phase (e.g., saltwater).
Separation Methods: Include filtering (removal of solids from liquids), sifting (separating different-sized solids), and evaporation (separating solids from homogeneous mixtures).

Reaction Rates and Indicators

Factors to Speed Up Chemical Reactions: Increase concentration, surface area, temperature, or add a catalyst.
Chemical Reaction Indicators: Observable signs such as bubble formation, temperature changes, precipitate formation, or color changes.

Thermodynamics in Reactions

Endothermic Reaction: Absorbs heat, lowering surrounding temperature.
Exothermic Reaction: Releases heat, raising surrounding temperature.

Fundamental Measurements

Density: The ratio of mass to volume, provides insight into how substances will interact.
pH: Gauge of whether a substance is acidic or basic.
Characteristic Property: A property that remains constant despite sample size variations.

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Test your knowledge of essential chemistry concepts with these flashcards. Learn about atoms, elements, and atomic mass to solidify your understanding of matter and its properties. Perfect for review before exams or for quick learning sessions.