Chapter 1: Structure of the Atom

Chemical reactions

are simple arrangements of atoms from one combination to another in small whole- number ratios.

J J Thompson

Electrons were discovered in 1879 by , when he determined that cathode rays were fundamental parts of matter he called electrons.

energy of electromagnetic waves

The is proportional to the frequency and inversely proportional to the wavelength.

1900

In , Max Planck described light as packets, or quanta, of energy called photons.

William Crookes

Sir , the scientist who developed cathode ray tubes in the 1870s, originally thought cathode rays to be negatively charged molecules instead of electrons.

previous s

In order to maintain charge stability within an atom, certain atoms will "unfill "their sublevel to fill their new d sublevel.

Hunds Rule

- All p, d, or f orbitals in a sublevel must be filled with one electron before a second electron is allowed to pair in any orbital.

Alpha

particles- particles are complicated, but the only thing you need to remember about them right now is that they are positively charged particles.

sublevel of the atom

Each contains one or more electron orbital.

discrete wavelengths

The colors consist of of light (line spectra) and not a uniform rainbow found when white light is separated by a prism.

Orbitals

are designated as s, p, d, or f, according to the sublevel they are in.

Visible light

is only a small part of the electromagnetic spectrum.

Electron configuration

- Each element has its own unique sequence of orbitals that can, once again, be derived using the periodic table.

Matter

- In chemistry, is any physical substance that has mass and takes up space by having volume.

Uncertainty principle

- The states that the position and momentum of any particle can not both be known at exactly the same time.

Niels Bohr

created a theory that electrons move around the nuclei in circular orbits and that electrons only exist in certain "allowed orbits ..

Sublevels

are corresponding letters of s, p, d, and f.

Oil drop experiment

- This was an experiment performed by Robert Millikan, which allowed him to calculate the charge of an electron to be- 1.60 x 10^- 19 columbs.

proton

The has a mass of 1.67 x 10^- 24 gram.

Orbital diagrams

can also be drawn in staggering heights to show the energy differences between orbitals.

electromagnetic radiation

All may be considered as waves that are defined by their wavelengths and frequencies.

Neutron

- The neutron is the third major particle that marks up the atom, but has no charge.

Spectroscope

- A spectroscope is a machine that is used to produce and record the light /color spectra of a particle for examination.

John Dalton

Daltons atomic theory- created a scientific theory on the nature of matter and atoms, consisting of three major components.

Wavelength

has units of meters and any necessary appropriate prefix.

Plancks constant

- The proportionality constant, h, has a value of 6.63 x 10 ^- 34.

Frequency

- The frequency is defined as the number of waves that pass a point in space in one second.

Molecule

- A molecule is a combination of two or more atoms.

principal energy level

The number of sublevels possible in each is equal to the value of n for that energy level.

Atoms

are often referred to as the basic building block of life.

Orbitals

- An orbital is a region o space that has a high electron density.

Proton

- A proton is a basic unit of positive charge in the atom.

Wavelength

- The wavelength is the distance between two repeating points on a sine wave.

Atom

- An atom is the smallest unit into which matter can be divided.

Sublevels

(Subshells)- Each principal energy level within an atom contains one or more sublevels or subshells.

proton

The has a positive charge which is exactly equal in magnitude to the electron charge.