Chemistry Chapter 2

1,760

Kelvin, Celsius, and Fahrenheit

Add 273.15

Subtract 273.15

4

9°F over 5°C

5°C over 9°F

32°F

(T_F-32°F)by 5°C over 9°F

T_C by 9°F over 5°C + 32°F

Extraction of metals from ores

Robert Boyle

Antoine Lavoisier

A given compound always contains exactly the same proportion of elements by mass

When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 g of the first element can always be reduced to small whole numbers

• Each element is made up of tiny particles called atoms
• The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways
• Chemical compounds are formed when atoms of different elements combine with each other. A given compound always has the same relative numbers and types of atoms
• Chemical reactions involve reorganization of atoms- changes in the way they are bound together. The atoms themselves are not changed in a chemical reaction

Mass is often determined by comparison to a standard mass

• 1. At the same temperature and pressure, equal volumes of different gases contain the same number of particles
•      Makes sense if the distances between the particles in a gas are very great compared with the sizes of the particles
•      Under these conditions, the volume of a gas is determined by the number of molecules present, not by the size of the individual particles

J.J. Thomson

A partially evacuated tube

A stream of negatively charged particles

e/m= -1.76 × 10^g C/g

[e represents the charge on the electron in coloumbs (C) and m represents the electron mass in grams]

The electrons are like raisins dispersed in a pudding (the positive charge cloud)

Spontaneous emission of radiation by uranium

Gamma (y) rays, beta (β) particles and alpha (a) particles

A high-energy "light"

A high-speed electron

has a charge twice that of the electron and with the opposite sign (2+)

An atom with a dense center of a positive charge (aka the nucleus)with electrons moving around the nucleus at a distance that is large relative to the nuclear radius

Have a positive charge equal in magnitude to the electron's negative charge

Virtually have the same mass as a proton but no charge

It's small size compared to the overall size of the atom and its high density

The electrons constitute most of the atomic volume thus are the parts that "intermingle" when atoms combine to form molecules

Atoms that have the same number of protons but a different number of neutrons

Number of protons in an element

The total number of protons and neutrons

John Dalton

The forces that hold atoms together in compounds

One way atoms form bonds by sharing electrons

A collection of atoms that result from a covalent bond

A method for representing molecules in which symbols for the elements are used to indicate the types of atoms and subscripts are used to indicate the relative numbers of atoms

A model of methane that shows the relative sizes of the atoms as well as their relative orientation in the molecule

A method for representing molecules in which the individual bonds are shown (indicated by lines)

An atom or a group of atoms that has a net positive or negative charge

A positive ion

An ion with a negative charge

A solid consisting of oppositely charged ions

A chart that shows all the known elements and gives a good  deal of information about each

Elements that have characteristic physical properties such as efficient conduction of heat and electricity, malleability, ductility (they can be pulled into wires), and often a lustrous appearance

They tend to lose electrons to form positive ions

Bond to each other by forming covalent bonds

They tend to gain electrons to form negative ions

Elements in the same vertical columns on the periodic table that have similar chemical properties

Very active elements that readily form ions with a 1+ charge when they react with nonmetals

Form ions with a 2+ charge when they react with nonmetals

Form diatomic molecules

They all exist under normal conditions as monatomic gases and have little chemical reactivity

Horizontal rows in the periodic table

Compounds composed of two elements

Contain a positive ion (cation) always written first in the formula and a negative ion (anion)

• 1. The cation is always named first and the anion second
• 2. A monatomic cation takes its name from the name of the element 
• 3. A monatomic anion is named by taking the root of the element name and adding     -ide

• When the metal forms more than one type of ionic compound with a given anion
• In a case such as this, the charge on the metal ion must be specified
• Roman numerals indicate the charge of the ion

The ion with the higher charge has a name ending in -ic, while the ion with the lower charge has a name ending in -ous

• Only in cases where more than one ionic compound forms between a given pair of elements
• Elements that only form one cation do not need roman numerals (group 1A, group 2A, and aluminum)

Anions that contain an atom of a given element and different numbers of oxygen atoms

• Formed between two nonmetals
• These compounds do not contain ions, but are named very similarly to binary ionic compounds

• The first element in the formula is named first, using the full element name
• The next element is named as if it were an anion
• Prefixes are used to denote the number of atoms present; the prefix mono is never used

A molecule in which one or more H⁺ ions are attached to an anion

If the name of the anion ends in -ide, the acid is named with the prefix hydro- and and the suffix -ic

The acidic name is formed from the root name of the anion with the suffix of -ic or -ous, depending on the name of the anion

the suffix -ic is added to the root name

The -ite is replaced with -ous