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 numbers

Hund’s rule

For any set of orbitals of the same energy, that is, for any subshell, the ground state electron configuration is obtained by placing the electrons in different orbitals of this set with parallel spins. No orbital in the subshell contains two electrons until each orbital contains one electron.

Full valence shell

Completely non-reactive

Moderately full valence shell

Typically less-reactive

Nearly full / Nearly empty valence shell

Very reactive due to only having or only missing 1 electron in the valence shell

Octet Rule

Most atoms prefer to have eight valence electrons, even if this means their valence shell is not full

Ionization energy

the minimum energy required to remove an electron completely from the gaseous atom or ion

Ground state

Stationary state of lowest energy

Excited state

Allowed state of higher energies than the ground state

When an electron jumps to an outer orbit, it must _____ energy

Absorb, in the form of a photon

When an electron moves to an inner orbit, it _____ energy

Emits, in the form of a photon

Alkali and Alkaline metals, groups 1 and 2 on the periodic table

S-Block

Main-group elements, groups 13-18 on the periodic table

P-Block

Transition metals, groups 3-12 on the periodic table

D-Block

Inner transition metals, lanthanides and actinides

F-Block

When many of the electron spins are aligned in a given domain, it produces a _____

Net magnetic field

In certain strongly magnetic materials, known as _____, electron spins do not pair, or cancel, completely. As a result, there is a strong coupling or interaction between neighboring atoms, leading to the formation of large groups of atoms called magnetic domains.

Ferromagnetic materials

Above a certain critical temperature, called the _____, domain coupling is destroyed by the increased thermal oscillations and ferromagnetic material loses its ferromagnetism

Curie Temperature

Law of Poles

Like magnetic poles repel each other, and unlike magnetic poles attract each other.

Magnetic Dipoles

The magnetic field emanating from a north pole will always terminate on a south pole. If you break a magnet in half, it automatically generates opposing poles on the broken ends.

Magnetism is produced by _____

Electric charges in motion, such as electric currents or orbiting atomic electrons

Electric fields are produced by

Stationary electric charges

A magnetic field is defined by ____

The force it exerts on moving charges, SI unit of Tesla (T)

Permeability

A physical constant that describes the properties of the magnetic field in a vacuum

Permittivity

A physical constant that describes the properties of the electric field in a vacuum

A chemical bond is formed when _____

two or more atoms unite to form a more stable unit through the transfer or sharing of electrons

The measure of tendency with which an atom in a molecule attracts the electrons in it;s covalent bonds with other atoms is called _____

Electronegativity

The energy released from an atom when an electron is bound to it during bonding is called _____

Electron affinity

The sharing of electrons between two atoms results in a _____

Covalent bond

Covalent bonds between two molecule of like or different elements are known as _____

Diatomic Molecules

Homonuclear

Diatomic molecules in which both nuclei are the same

Heteronuclear

Diatomic molecules in which the two atoms are different

Paramagnetic properties

When there exists weak attraction between a molecule and the poles of a magnet

Diamagnetic properties

When there exists weak repulsion between a molecule and a magnetic field

Ionic bond

Occurs when an atom with low ionization potential merges with (“donates” an electron to) an atom with a high affinity for electrons.

Low ionization potential

When it takes very little energy to strip an electron away from the atom (usually atoms with 3 or fewer valence electrons)

When an atom loses an electron, it will have a net positive charge, making it a _____

Positive Ion

When an atom with an unfilled valence shell can obtain extra electrons, giving it a net negative charge, making it a _____

Negative Ion

Metallic elements lose electrons to become positively charged ions called _____

Cations

Nonmetallic elements gain electrons to become negatively charged ions called _____

Anions

_____ substances are composed of only one type of atom

Atomic

_____ substances are composed of more than one type of atom

Molecular

The quantity of a substance who’s mass in grams is numerically equal to the formula mass of the substance is called a _____

Mole

Avogadro’s Number

The experimental determination that one mole of any substance contains 6.022 × 10²³ formula units.

Law of Conservation of Mass

In a chemical reaction, the total mass of the reacting substances is equal to the total mass of the product formed.

Stoichiometry

The calculation of the quantities of elements or compounds involved in chemical reactions

Empirical formulas

The simplest form of chemical formulas i.e. CH₂ is the reduced way to represent the ratio of carbon to hydrogen atoms

Molecular formulas

Multiples of the empirical formula indicate the formula mass i.e. C₃H₆ is a factor of 3 times the empirical formula for methylene

Reactants

The substances which interacted to yield end products

Limiting reactant

the reactant that is consumed completely and thereby limits the amount of product formed

Excess reactant

Any other reactants remaining after a chemical reaction

Products

The result of the interaction of two or more substances

Theoretical yield

The amount of products produced from a complete reaction of the limiting reactant

Actual yield

The mass of the product that actually is obtained from a chemical reaction

Percentage yield

Representation of the ratio of actual yield to the theoretical yield.