9S100 Block 3 - Inorganic Chemistry - Section 2

Dalton’s Atomic Theory

Provides explanation of both the law of constant composition and the law of conservation of mass; Matter is composed of small, indivisible particles called atoms

Atoms of the same element

All have the same mass and are identical in all respects, including chemical behavior

Atoms of different elements

Differ in mass as well as chemical behavior

Chemical compounds

Composed of two or more atoms of different elements joined together.

Molecule

The particle that results when any two or more atoms join together

Chemical Reaction

Atoms involved are rearranged, separated, or recombined to form new substances.

Nucleus

Composed of protons and neutrons

Protons

Positively charged

Mass of ~1.673 × 10^-27Kg

Neutrons

Electrically Neutral

Mass of ~1.674 × 10^-27Kg

Electrons

Negatively charged

Mass of ~9.11 × 10^-31Kg

Ion

Describes an atom that is positively or negatively charged

Rutherford-Bohr Model

AKA Planetary or Solar System Model, shows negatively charged electrons orbiting a positively charged nucleus

Size of an atom is generally considered to be _______

The “space” occupied by the electrons

Schrodinger / Quantum Model

Instead of restricting the electron to certain, precisely defined orbits, the wave equation provides one or more functions, called wave functions, associated with each allowed energy

Probability Density

Probability that the electron will be done in small volume surrounding a point. It says we cannot locate the electron position precisely; we can only assign a probability that the electron is in a certain region of space

Quantum Numbers

Defines the atomic orbitals of an atom’s electrons. These orbitals are a special case of wave functions from quantum mechanics

Elements

Pure chemical substance composed of one type of atom; it cannot be chemically separated into simpler substances

Molecules

The smallest unit of a compound that can still retain the characteristics of the compound, fromed by chemical action in atoms

Compounds

A substance that can be decomposed into two or more simpler substances only by chemical means

Isotopes

An element with more or less than the normal number of neutrons

Nuclides

Elements and their Isotopes

X-Symbol

Chemical symbol for an element (H, Fe, K, etc.)

Z-Number

Atomic number that is equal to the number of protons

A-Number

Mass number, which is approximately equal to the sum of the number of protons and neutrons

Periods / Rows

The seven horizontal rows that correspond to the number of orbital shells each element has

Electron shells

Electrons of an atom are rearranged in a definite, pattern forming energy, levels or shells

Shells are identified by letters such as: ________

K / n=1 (ground state)

L / n=2

M / n=3

etc.

Group 1

Alkali Metals - Very reactive as they have a single electron in their valence shell that is very easily removed through ionization

Group 2

Alkaline Earth Metals - Compounds that often occur in alkaline soil deposits. When heated, these metals all burn brightly in oxygen to form white, crystalline, ionic oxides

Group 17

Halogens - Are highly reactive due to their nearly full valence shell

Group 18

Noble Gases - Completely non-reactive, as they have a full valence shell

Groups 3-12

Transitional Metals - Span the region of the periodic table where the transition from metallic to nonmetallic behavior of the main-group elements occurs

Inner Transitional Metals

Elements in these two series have remarkably similar chemical properties

Lanthanides

Rare-Earth Metals - Once thought to occur only in very small quantities

Actinides

Radioactive, most of which do not occur in nature, but are produced in nuclear explosions

Metal Qualitative Properties

High electrical and thermal conductivity

Electrical resistance increases with increasing temperature

Malleability and ductility is high

Non-volatile and possess high melting points

Semimetals (Metalloids)

Intermediate electrical and thermal conductivity

Electrical resistance decreases with increasing temperatures

Are brittle

Volatile and possess low melting points

Nonmetals

Low electrical and thermal conductivity

Electrical resistance is insensitive to temperature

Neither malleable nor ductile

Volatile and possess low melting points

Trans-Uranium elements

With the exception of trace quantities of plutonium, elements beyond uranium (Z>92) have not been found in nature but are synthesized in nuclear reactors

Radioactive elements

All elements with atomic numbers greater than bismuth (Z>83) are unstable, thereby making them radioactive

Atomic Orbitals

Orbit of an electron is not a classical path with a definite trajectory, rather, the orbit describes the most probable region in which the electron may be found.

Principle Quantum Number

n (shells)

Azimuthal Quantum Number

l (subshells)

Magnetic Quantum Number

m_l (Spatial Orientation)

Spin Quantum Number

m_s (Electron Spin)

Pauli Exclusion Principle

No two electrons in the same atom can have the same set of four Quantum