General Chemistry Intro

All mass consists of tiny particles called atoms

Nucleus surrounded by electrons Necleons: protons and neutrons that make up the nucleus, approximately equal in size and mass

Protons and neutrons are held together to form the nucleus by this force Stability can be measured by binding energy: energy that would be required to break the nucleus into individual protons and neutrons

One angstrom is 10^-10 m Radius of nucleus on order of 10^-14 Angstroms

1 to 3 Angstroms

Electron: 5.5 x 10^-4 amu Proton: 1.0073 amu Neutron: 1.0087 amu

Matter is composed of atoms Atom is composed of mostly empty space

Symbol, e Equal to 1.6 x 10^-19 Coulombs or C (SI unit for charge) Charge of an electron or proton

Building blocks of compounds and cannot be decomposed into simpler substances by chemical means

Number of protons, provides identity of element Each element has a unique number of protons

Number of protons plus neutrons Varies depending on the number of neutrons Mass number of element is approximately equal to atomic weight or molar mass of element

Two or more atoms of the same element that contain different numbers of neutrons Nucleus of specific isotope is called nuclide Isotopes have similar chemical properties

{1}^H, {2}^H, {3}^H Protium, Deuterium, and Tritium 99.98% of naturally occurring hydrogen is protium

{12}^C, {13}^C, {14}^C 6 neutrons, 7 neutrons, and 8 neutrons, respectively

Number of electrons and protons are not equal in atom Atom carries a charge and is not electrically neutral Cations: positively charged, have fewer electrons than protons Anions: negatively charged, have more electrons than protons Salt: neutral compound composed of positive and negative ion together

Creates isotope, creates ion, and changes to another element, respectively

Atomic radius never changes, ionic radius does Ionic radius gets smaller because positive charge of the nucleus exerts a greater attractive force on each valence electron, pulling them closer the nucleus Loss of electron reduces repulsive forces between electrons further contributing to decrease in size Loss of electron also increases Z_eff for each electron Ionic radius gets larger

Table that lists elements from left to right in order of their atomic numbers Each horizontal row is called a period Each vertical column is called a group or family Elements in the same family share similar chemical and physical properties

Number 1 through 18 left to right is newer Separate groups into A and B and then number with Roman numerals is older

Nonmetals on right, metals in middle and left, metalloids along diagonal separating the metals and nonmetals

Large atoms that tend to lose electrons to form positive ions and oxidation states Atoms in a sea of electrons, fluid-like nature of valence electrons Metallic character: ductility (easily stretched), malleability (easily hammered into thin strips), thermal and electrical conductivity, and luster Metal atoms easily slide past each other Electrons move easily from one metal atom to the next, transferring energy or charge (heat or electricity) All metals except mercury exist as solids at room temperature Typically lose electrons to become cations (form ionic bonds)

Group (1): alkali metals, IA Group (2): alkaline earth metals, IIA Group (16): oxygen group, VIA Group (17): Halogens, VIIA Group (18): Noble gases, VIIIA

Lanthanides on top Actinides on bottom

Diverse appearances and chemical behaviors Molecular substances generally made with nonmetals, because tend to covalently bond Lower melting points than metals Tend to form anions, reacting with cations to form ionic compounds