Chapter 2: ATOMS, MOLECULES, AND IONS

Cathode rays

Cathode rays

________ passed from the negative electrode to the positive.

Perspective drawings

________ use wedges and dashed lines to depict bonds that are not in the plane of the paper.

Sodium chloride

________, which we know better as common table salt, is an example of an ionic compound, a compound made up of cations and anions.

James Chadwick

________ discovered neutrons in 1932 and Rutherford identified protons in 1919.

Robert Millikan

In 1909, ________ (1868- 1953) of the University of Chicago succeeded in measuring the charge of an electron by performing the experiment.

John Dalton

________ (1766- 1844), the son of a poor English weaver, began teaching at age 12.

gas phase species

The ________ must be converted to positively charged particles called ions.

Dalton

________ and his successors have no direct proof for atoms.

net charge

The ________ on an ion is represented by a superscript.

Henri Becquerel

In 1896 the French scientist ________ (1852- 1908) discovered that a compound of uranium spontaneously emits high- energy radiation.

Thomson

________ reasoned in the early 1900s that since electrons contribute just a small proportion of an atom's mass, they probably contribute an equally small fraction of its size.

Chain length

________ affects alkanes and alcohols.

electrons

If ________ are removed from or added to an atom, a charged particle called an ion is formed.

Oxygen

________ also exists in another molecular form known as ozone.

Marie Curie

In 1911, ________ won a second Nobel Prize, this time in chemistry for her discovery of the elements polonium and radium.

Prefixes

________ are used when the series of oxyanions of an element extends to four members, as with the halogens.

Rutherford

________ explained the results by proposing the nuclear model of the atom, in which most of each gold atom's mass and positive charge are concentrated in a tiny, dense nucleus.

chemical properties

Elements in a group often exhibit similarities in physical and ________.

ethane

For example, methane, ________, and propane are all color- less gases under normal conditions, whereas methanol, ethanol, and propanol are colorless liquids.

Democritus

________ (460- 370 bce) and other early Greek philosophers described the material world as made up of tiny indivisible particles that they called atomos, meaning "indivisible "or "uncuttable ..

alkane

Each ________ has a name that ends in- ane.

Acids

________ are an important class of hydrogen- containing compounds, and they are named in a special way.

Calcium bicarbonate

________ is also called calcium hydrogen carbonate.

atom

The ________ has electrons, protons, and neutrons.

noble gases

The ________ are chemically nonreactive elements that form very few compounds.

helium

The elements ________ (He), neon (Ne), and argon (Ar) are all nonreactive gases.

Space filling models

________ depict what a molecule would look like if the atoms were scaled up in size.

chemical nomenclature

The system used in naming substances is called ________, from the Latin words nomen (name) and calare (to call)

positive charge

An ion with a(n) ________ is a cation (pronounced CAT- ion); a negatively charged ion is an anion (AN- ion)

Compounds

________ that contain only carbon and hydrogen are called hydrocarbons.

Organic compounds

________ contain carbon and hydrogen, often in combination with oxygen, nitrogen, or other elements.

molecular formula of a substance

The ________ does not show how its atoms are joined together.

Nonmetals

________ generally differ from metals in appearance and in other physical properties.

tube electrodes

The ________ radiated when high voltage was applied.

elements lithium

The ________ (Li), sodium (Na), and potassium (K) are all soft, very reactive metals, for example.

Henri Becquerel

In 1903, ________, Marie Curie, and her husband, Pierre, were jointly awarded the Nobel Prize in Physics for their pioneering work on radioactivity (a term she introduced)

Electrons

________ are attracted to the protons in the nucleus by the electrostatic force that exists between particles of opposite electrical charge.

alcohol

A(n) ________, for example, is obtained by replacing an H atom of an alkane with an- OH group.

Atoms

________ have no net electrical charge since they have equal electrons and protons.