Chemistry Vocabulary: Semester 1

Front 1

Hypothesis

Back 1

a testable statement

Front 2

Theory

Back 2

a statement supported by data or facts

Front 3

Fact

Back 3

an observation we can all agree upon

Front 4

Qualitative

Back 4

descriptive

Front 5

Quantitative

Back 5

numerical

Front 6

Model

Back 6

a visual representation

Front 7

System

Back 7

a region of matter designated for study

Front 8

Quantity

Back 8

something that has size, magnitude, or amount

Front 9

Precision

Back 9

the closeness amongst a set of measurements

Front 10

Accuracy

Back 10

the closeness of measurements to the accepted value

Front 11

Chemistry

Back 11

the study of matter and its changes

Front 12

Chemical

Back 12

a substance with a fixed composition

Front 13

Organic Chemistry

Back 13

the study of carbon-based chemicals

Front 14

Inorganic Chemistry

Back 14

the study of non-carbon based chemicals

Front 15

Physical Chemistry

Back 15

the study of energy

Front 16

Analytical Chemistry

Back 16

the study of the formula of a piece of matter

Front 17

Biochemistry

Back 17

life-related chemistry

Front 18

Theoretical Chemistry

Back 18

the mathematical model and prediction side of chemistry

Front 19

Basic Research

Back 19

research done to further our understanding of chemistry

Front 20

Applied Research

Back 20

research trying to solve a problem

Front 21

Technology Research

Back 21

research done in response to consumer interest

Front 22

Mass

Back 22

the amount of matter in an object

Front 23

Volume

Back 23

the amount of space in an object

Front 24

Matter

Back 24

anything that has mass and ocupies volume

Front 25

Atom

Back 25

the smallest unit of an element to maintain its identity

Front 26

Element

Back 26

a pure substance that cannot be broken down

Front 27

Compound

Back 27

made up of two or more elements

Front 28

Property

Back 28

a characteristic that defines an entire set of substances

Front 29

Extensive Property

Back 29

depends on the amount of matter

Front 30

Intensive Property

Back 30

does not depend on the amount of matter

Front 31

Physical Property

Back 31

can be observed without changing the identity of a substance

Front 32

Physical Change

Back 32

a change that does not involve a change in identity

Front 33

Change of State

Back 33

physical change of a substance from one state to another

Front 34

Law of Conservation of Mass

Back 34

mass can neither be created or destroyed

Front 35

Law of Definite Proportions

Back 35

a chemical compound always contains the same elements in the same proportions by mass

Front 36

Law of Multiple Proportions

Back 36

if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers

Front 37

Nuclear Forces

Back 37

the attractive forces within the nucleus that hold protons and neutrons together

Front 38

Atomic Number

Back 38

the number of protons in each atom of an element; determines the identity and properties of the element

Front 39

Isotopes

Back 39

atoms of the same element with different masses (different number of neutrons)

Front 40

Mass Number

Back 40

the total mass of protons and neutrons in the nucleus of an atom

Front 41

Nuclide

Back 41

a specific isotope of an element (tells the mass number and atomic number)

Front 42

Average Atomic Mass

Back 42

the weighted average (based on abundance) of atomic masses of all naturally occurring isotopes of an element

Front 43

Mole

Back 43

the amount of a substance that contains Avogadro's number of particles

Front 44

Molar Mass

Back 44

the mass of one mole of anything

Front 45

Quantum Energy

Back 45

the minimum amount of energy that can be lost or gained by an electron

Front 46

Photons

Back 46

a particle of electromagnetic radiation with no mass carrying 1 quantum of energy

Front 47

Ground State

Back 47

the lowest energy of an atom

Front 48

Excited State

Back 48

a state in which an atom has a higher potential energy

Front 49

Aufban Principle

Back 49

an electron always goes into the LOWEST energy level that is not full

Front 50

Polyexclusion Principle

Back 50

no two electrons can have the exact same set of four quantum numbers

Front 51

Hund's Rule

Back 51

orbitals in the same sublevel are all occupied by one electron before any orbital can get two electrons

Front 52

Periodic Law

Back 52

when elements are arranged according to increasing atomic number, elements with similar properties appear at regular intervals

Front 53

Periodic Table

Back 53

an arrangement of the elements in order of their atomic numbers so that elements with similar properties are in the same column

Front 54

Periodicity

Back 54

refers to the number of orbitals; the difference in atomic mass determines this

Front 55

Periodic Property

Back 55

a property that occurs periodically as you go down the column

Front 56

Atomic Radius

Back 56

half the distance between the nuclei of identical atoms that are bonded together

Front 57

Ionization Energy

Back 57

the energy required to remove on electron from a neutral atom

Front 58

Electron Affinity

Back 58

the energy change that occurs when an electron is acquired by a neutral atom

Front 59

Ion

Back 59

a particle that is positively charged; an atom that has gained or lost electrons

Front 60

Cation

Back 60

a positively charged ion

Front 61

Anion

Back 61

a negatively charged ion

Front 62

Valence Electrons

Back 62

those electrons that are available to be lost or gained or shared in the formation of chemical compounds

Front 63

Electronegativity

Back 63

a measure of the ability of an atom in a compound to attract electrons from another a tom in the compound

Front 64

Covalent Network

Back 64

made up of atoms covalently bonded to all other atoms int he structure, in a lattice

Front 65

Ionic Compound

Back 65

is composed of positive and negative ions that are combined in a lattice so that the charges balance

Front 66

Formula Unit

Back 66

the simplest collection of atoms from which an ionic compounds' formula can be established

Front 67

Bond Length

Back 67

the distance between two bonded atoms at their minimum potential energy

Front 68

Bond Energy

Back 68

the energy required to break a chemical bond

Front 69

Octet Rule

Back 69

chemical compounds tend to form so that each atom-by gaining, losing, or sharing electrons-has an octet of electrons in its highest occupied energy level

Front 70

Chemical Bond

Back 70

a mutual attraction between the nuclei and electrons of different atoms which holds the atoms together

Front 71

Ionic Bonding

Back 71

results from the attraction between two ions

Front 72

Covalent Bonding

Back 72

results from the sharing of electron pairs between atoms

Front 73

Molecule

Back 73

a neutral group of atoms held together by covalent bonds

Front 74

Chemical Formula

Back 74

shows the relative numbers of atoms of each kind in a chemical compound using atomic symbols and subscripts

Front 75

Molecular Formula

Back 75

shows the types and numbers of atoms in a single molecule of a molecular compound

Front 76

Lattice Energy

Back 76

the energy released when a lattice is formed

Front 77

Polyatomic Ion

Back 77

a charged group of covalently bonded atoms

Front 78

Metallic Bonding

Back 78

results from the attraction between metal atoms and the surrounding sea of electrons

Front 79

Hydrogen Bonding

Back 79

an intermolecular force that results from the bond between hydrogen and a highly electronegative atom

Front 80

Empirical Formula

Back 80

the smallest whole-number ratio of atoms in a compound

Front 81

Relative Atomic Mass

Back 81

the mass of an isotope relative to 1/12 of the mass of a carbon-12 atom

Front 82

Proton

Back 82

a subatomic particle found in the nucleus of every atom. The particle has a positive electrical charge

Front 83

Neutron

Back 83

a subatomic particle found in the nucleus of every atom except hydrogen. It has no electrical charge and are extremely dense.

Front 84

Electron

Back 84

the negatively charged particles of atom

Front 85

Orbital

Back 85

regions of space around the nucleus of an atom where an electron is likely to be found; allow atoms to make covalent bonds (s, p, d, and f)

Front 86

Heisenburg Uncertainty Principle

Back 86

it is impossible to tell the velocity and the location of the electron at the same time (contradicts Bohr's model of the atom).

Front 87

Quantum Model of the Atom

Back 87

3D. We only know the probable location of an electron, but the electrons exist in 3D orbitals. Has a concept of energy orbitals.

Front 88

Bohr Model of the Atom

Back 88

2D. Electrons exist in well-defined two dimensional orbits. Has a concept of energy orbitals.

Front 89

Metal

Back 89

a solid material that is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivity

Front 90

Substance

Back 90

a particular kind of matter with uniform properties

Front 91

Pauli Exclusion Principle

Back 91

states that no two electrons can have the same four quantum numbers

Front 92

Hydrogen Line Spectrum

Back 92

When an electron collides with a gas, the electron bounces to the next orbit. As it goes back to the original orbit, the energy omitted goes out in the form of light

1) Pass an electric current through a tube of hydrogen gas.

2) There are collisions between electrons in the current and the gas molecules

3) As a result, the molecules (electrons) go from ground state to excited state.

4) When they fall from excited to ground, a photon of light is emitted.

5) The blended light is split using a prism.