Semester 1 Flashcard

Accuracy
Referring to the closeness of a measurement to the true or accepted value.

Actual Yield 

The measured amount of product actually collected from a reaction.
Alkali Metals
The elements of Group 1 of the periodic table (except hydrogen).

Alkaline Earth Metals 

The elements of Group 2 of the periodic table.

Atom 

The smallest particle of an element that can exist either alone or in combination with other atoms.

Atomic Mass 

The relative atomic mass of an atom or subatomic particle, measured in atomic mass units (u).

Atomic Mass Unit (u) 

A unit of mass, abbreviated u, that is exactly 1/12 the mass of a carbon-12 atom. 1 u equals 1.66 x 10-24 grams.
Atomic Number 
The number of protons in the nucleus of one atom of an element.

Atomic Radius 

One-half the diameter of an atom, measured by taking half of the distance between the centers of two atoms of the same element that are bonded together.
Aufbau Principle
An electron occupies the lowest energy orbital, closest to the nucleus, that can receive it.
Avogadro’s Number
6.022 x 1023, the number of particles in exactly one mole of a pure substance.

Binary Compound;

A compound composed of two different elements.
Calibrate
To make fine adjustments or divide into marked intervals for optimal measuring.
Celsius
A metric unit of temperature that has water freezing at 0 degrees and boiling at 100 degrees.
Chemical Change;
A change in which the atoms of one or more substances are rearranged to form one or more new substances.
Chemical Energy
Energy stored in the bonds of atoms and molecules.
Chemical Property
A property that describes a substance’s potential to undergo a reaction or chemical change because of its composition or bonding.
Chemistry
The study of the composition and structure of materials and the changes they undergo.

Control Variables 

The variables within an experiment that a scientist chooses to keep constant, or not to change, so that they will not affect the observations and data collected.

Covalent Bond 

A chemical bond in which electrons are shared between two atoms.

Covalent Compound 

A group of two or more atoms held together by covalent bonds to form a neutral compound.

Decomposition Reaction 

A reaction in which a single compound reacts to form more than one product.

Delocalized 

Not localized, or restrained, to a single atom or covalent bond within a molecule.

Density 

A materials mass divided by its volume, or its mass per unit volume.

Dependent Variable 

The one variable that will be observed or measured as a result of an experiment, to see how it was affected by the changes to the independent variable.

Dimensional Analysis 

A problem-solving method used in physics, chemistry, engineering, and mathematics that is based on treating units in calculations as algebraic factors or fractions.

Double Replacement Reaction 

A type of reaction in which the ions of two compounds exchange places in an aqueous solution to form two new compounds.

Effective Nuclear Charge 

The charge (from the nucleus) felt by the valence electrons after you have taken into account the number of shielding electrons that surround the nucleus.

Electrical Energy 

The movement of electrical charge.

Electromagnetic Radiation (EMR) 

Waves emitted by the vibration of electrical charges (often electrons) and composed of vibrating electric and magnetic fields that regenerate one another. The range of electromagnetic waves extends from radio waves to gamma rays, and is called the electromagnetic spectrum.
Electron
A negatively charged subatomic particle found in the area surrounding the nucleus of an atom.

Electron Affinity 

The energy involved when a neutral atom gains an electron.
Electronegativity
A measure of the attraction of an atom for the electrons in a chemical bond.
Element
Any material made of only one type of atom. All known elements are listed on the periodic table.

Empirical Formula


The formula of a compound in which the subscripts represent the lowest whole-number-ratio of the atoms.

Energy Level 

Areas of the electron cloud surrounding the nucleus, sometimes called shells, with increasing potential energy as they get farther from the nucleus.

English System 

A system of weights and measures based on the foot and pound and second and pint.

Excess Reactant 

The reactant that is not used up completely in a chemical reaction.

Exothermic Process 

A chemical or physical change that releases energy to the surroundings.

Fahrenheit 

An English System unit of temperature that has water freezing at 32 degrees and boiling as 212 degrees.

Formula Unit 

The formula of an ionic compound that represents the simplest whole number ratio of ions in the compound, not the actual number of each ion present in the crystal.
Frequency
The number of waves passing by a fixed point in a given amount of time. Frequency is often measured in waves per second.

Graduation 

A line that marks a measurement: such as on a ruler or graduated cylinder.

Gram 

A metric base unit of mass.

Gravitational Energy 

The potential energy of position.

Group 

The vertical columns of elements on the periodic table, also called families, numbered 1 to 18 from left to right.

Halogens 

The elements of Group 17 of the periodic table.

Heat 

The transfer of thermal energy from one substance to another due to the temperature difference between the two substances.

Hund’s Rule;

Orbitals within the same sublevel, with equal energy, are each occupied by one electron before any orbital in that sublevel is occupied by a second electron.

Hydrate;

A crystallized solid compound that contains water molecules within its structure.

Independent Variable;

The one variable that a scientist has chosen to change within an experiment in order to test a hypothesis.

International System of Units;

A system of measurement standards agreed upon by the global scientific community.
Ion
An atom that has a positive or negative charge due to a loss or gain of electrons.

Ionic Bond;

A chemical bond that results from electrostatic attraction between positive and negative ions.

Ionic Compound;

A compound composed of positive and negative ions that are combined in a ratio where the positive and negative charges cancel out.

Ionic Radius;

One-half the diameter of an ion.
Ionization Energy
The energy required to remove one electron from an element, resulting in a positive ion.

Isolated System;

A system in which neither energy nor matter is exchanged between the system and the surroundings.

Isotopes;

Atoms of the same element that have different masses due to their varying numbers of neutrons.

Kinetic Energy;

The energy of an object in motion.

Law;

A generalization that describes a variety of behaviors in nature, but does not attempt to explain.

Law of Conservation of Mass;

Matter is neither created nor destroyed during an ordinary physical change or chemical reaction.

Law of Multiple Proportions;

A basic law of chemistry that describes how atoms combine to form compounds in simple, whole number ratios.
Length
A measure used as a unit to estimate distances.

Limiting Reactant;

The reactant that controls the amount of product able to be produced by a chemical reaction because it is used up completely.

Line Spectrum;

A spectrum showing only certain wavelengths.

Liter;

A metric base unit of volume.

Magnetic Quantum Number;

Symbolized by ml, indicates the orientation of an orbital within a sublevel.

Mass;

A measure of the amount of matter in a substance.

Mass Number;

The total number of protons and neutrons in the nucleus of a given atom.

Matter;

Anything that has mass and volume.
Measurement;
The dimensions, quantity, or capacity of a substance as determined by comparison with a standard.

Mechanical Energy;

The movement of objects from one place to another. Meter: The SI standard, or base, unit for length.

Metalloids;

An element that has some properties characteristic of metals and others characteristic of nonmetals, and is a semiconductor.
Metals
An element that is a good conductor of heat and electricity.

Meter;

The SI standard, or base, unit for length.

Metric System;

A system of measuring units based on the power of ten.

Molar Mass;

The mass of one mole of a pure element or compound, given in the unit g/mol.
Mole;
The mole is the SI unit for the amount of a substance. It is equal to Avogadro’s number, 6.02 x 1023, and was determined using the element carbon as its standard.
Molecule
Another name for a chemical compound.

Neutron 

An electrically neutral subatomic particle found in the nucleus of an atom.

Noble Gases 

The elements of Group 18 of the periodic table.
Nonmetals
An element that is a poor conductor of heat and electricity, usually found toward the right side of the periodic table.

Non-polar Covalent Bond 

A covalent bond in which the atoms have an equal attraction for the shared electrons.

Orbital 

A three dimensional region around the nucleus in which two particular electrons can be located.

Pauli Exclusion Principle 

No two electrons in the same atom can have the same set of four quantum numbers.

Percent Yield 

The ratio of the actual yield to the theoretical yield, multiplied by 100 to make it a percentage.

Period 

The horizontal rows of elements on the periodic table, numbered one to seven from the top down.

Physical Change 

A change in which one or more physical properties of a substance change without changing the chemical identity of the substance.

Physical Property 

A property that can be observed or measured without changing the chemical identity of the substance.

Polar Covalent Bond 

A covalent bond where the atoms have an unequal attraction for the shared electrons.

Polyatomic Ion 

A charged group of covalently bonded atoms.

Potential Energy 

The energy that an object has because of its position or composition.

Precision 

Referring to the agreement among a set of measurements made of the same quantity in the same way.

Principal Quantum Number 

Symbolized by n, indicates the main energy levels surrounding a nucleus.
Products
The new substances that are formed or produced by a chemical reaction.

Proton 

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

Pseudoscience 

A practice or a belief that claims to be science, but does not follow the scientific method or is not testable.

Radiant Energy 

Electromagnetic energy that travels in waves.
Reactants
The substances that are present at the beginning and undergo a chemical reaction.

Resonance 

The bonding in molecules that cannot be represented by one single Lewis structure because the electrons are delocalized.
Science
A body of knowledge and a process of gaining and validating that knowledge.

Scientific Method 

A logical approach to the solution of problems that lend themselves to investigation by observing, generalizing, theorizing, and testing.

Scientific Notation 

Numbers written in the form M x 10n where M is a number greater than one and less than 10 and n is an integer.

Significant Figures 

All digits in a measurement that are known with certainty plus one final digit that is estimated and uncertain.

Single Replacement Reaction 

A type of reaction in which one element replaces a similar element within a compound.

SI Units 

International System of Units, the system of measurements agreed on by the global scientific community.

Sound 

The movement of energy through substances in longitudinal waves.

Spin Quantum Number 

Symbolized by ms, indicates the direction of an electron’s spin within an orbital.

Stoichiometry;

The use of dimensional analysis to calculate relationships between the amounts of reactants and products in chemical reactions.

Stored Mechanical Energy;

Energy that is stored in objects by the application of force.

Subatomic Particles;

Any particles of matter smaller than an atom, including protons, neutrons, and electrons.

Sublevel;

An area (s, p, d, f, etc.) within an energy level made up of a group of orbitals.

Synthesis Reaction;

A reaction in which two or more reactants combine to form one product.
Temperature
A measure of the average kinetic energy, caused by the vibration and movement of atoms and molecules, of a substance.

Theoretical Yield;

The maximum amount of product that can be produced by a given amount of reactant(s).

Theory;

A set of ideas that attempts to explain why things happen the way they do in the natural world.

Thermal Energy;

The internal energy in a substance caused by vibration of atoms and molecules.

Transition Metals;

The elements found between groups two and thirteen of the periodic table, starting in period four.

Valence Electrons;

The electrons in the s and p sublevels of the highest occupied energy level in an atom.
Variable
A factor or condition that can exist in differing amounts or types and can be changed or controlled within an experiment.

Volume;

The amount of space occupied by an object.

Wavelength;

The distance between corresponding points on adjacent waves. This distance is consistent throughout the entire sequence within a wave.

Weight;

A measure of the earth’s gravitational attraction for matter.

Weighted Average 

A weighted average accounts for the percent abundance and mass of each isotope in an element by taking the sum of each mass multiplied by its percent abundance.

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