Chemistry - Test 2 (Atomic Structure/Nuclear Chemistry)

Atom

Smallest particle of an element that retains properties of the element

Protons

Positively charged subatomic particle; found in nucleus of atom

Electrons (e^–)

Negatively charged subatomic particle; found around nucleus

Neutron

No charge subatomic particle; found in nucleus

Nucleus

Small center of the atom

Atomic number

Same as the number of protons

Mass number

Total number of protons and neutrons in an atom

Atomic Mass

Average mass of all naturally occurring isotopes of an element

Isotope Abundance

Amount a given isotope is found in nature, usually measured as a percentage

Isotope Notation

A way of abbreviating the name of an isotope

Radioactivity

Spontaneous emission of rays or particles from elements

Alpha radiation

Beta Radiation

Alpha decay

When helium (He) nuclei is emitted as an alpha particle

Beta decay

A neutron breaks apart into a proton and electron

Gamma Rays

High energy rays emitted by radioactive isotope

Gamma decay

Electron Capture

Occurs when nuclei have too few neutrons; Converting of a proton to a neutron, e^– is captured

Electron capture equation

Positron Emission

Proton changes to a neutron

Positron (e⁺)

Particle with mass of e^– but a positive charge; form of anti-matter

Positron Emission equation

Alpha particle

Helium-4

Beta Particle

An electron or a positron

Half Life

Amount of time for half of the nuclei to decay

Calculate Half-life

A = A₀ X (1/2)ⁿ

Nuclear Fission

The Process of bombarding certain isotopes with neutrons, causing them so split

Nuclear Fusion

Occurs when nuclei combine to from a heavier nucleus; usually Hydrogen (H)

Radioisotope

An unstable form of a chemical element that releases radiation as it breaks down and becomes more stable

Transmutation

Converting of an element to a different element; Can occur through decay or particles bombarding nucleus

Transuranium elements

Elements with atomic number >92; These elements are synthesized with nuclear accelerator

Calculating Atomic Mass

Multiply the mass # by the abundance of each isotope in nature, then add up the different isotopes

Calculating Mass Number

Protons + Neutrons

Density Calculation

Mass/Volume