Atomic Structure

Atomics structure study terms

Atomic number

the number of protons in the nucleus of an atom

Mass number

The total number of protons and neutrons in the nucleus of an atom

Proton

Positively charged particle in the nucleus of an atom

Neutron

Neutrally charged particle in the nucleus of an atom

Electron

Negatively charged particle; located outside the atomic nucleus

Nucleus

Center of an atom, very small portion of the atom where all of the mass and + charge is located

Isotopes

Atoms of the same element that have different numbers of neutrons

Energy level

Appear as rings around the nucleus representing specific distances which electrons of the same energy are be found

2 electrons

1st energy level

8 electrons

2nd & 3rd energy levels

Subatomic particle

Found within the atom, mainly protons, neutrons, and electrons.

Ion

A charged atom resulting from the gain or loss of electrons

1 AMU

Atomic mass unit, measure of the mass of a proton or neutron.

Bohr Model

More detailed model of the atom that shows all 3 subatomic particles.

Lewis structure

Less detailed model of the atom that shows only the chemical symbol and valence electrons. AKA dot model, better for showing many atoms bonded in a molecule.

Gold foil experiment

Rutherford's experiment that discovered the nucleus when the alpha particles were deflected by the dense portion of the atom.

Cathode ray tube

JJ Thomson's used this in his experiment that led to the discovery of the electron. New model has atoms containing charged particles.

Line spectra

Bohr suggests that electrons exist in energy levels. Colors of specific wavelengths relate to electron distance from nucleus.

Rutherford

Gold foil experiment, discovered nucleus

Bohr

Tested the emission spectrum of gasses; determined that electrons exit in energy levels.

Chemical symbol

A one or two letter representation of an element

Valence

Electrons on the outermost energy level of an atom

Thomson

discovered the electron

Atomic theory

States that all matter is composed of tiny particles called atoms.