Atom

Smallest partical of an element

Democritus

• Atoms are indivisible and indistructable
• No experiments. Noe scientific method.

Dalton

• Developed the Atomic theory
• Believed that a few kinds of atoms made up all matter
• Elements are composed of only one kind of atom; and compounds made from two or more atoms

Thompson

• Studied the cthode ray tube-made of particles that were negativley charged called them electrons
• Made the plum-pudding model - said that electrons were embeded on a postivley charged ball of matter

Rutherford

• Preformed the gold foil experiment (disproved plum pudding model)
• Said that atoms are mostly empty space

Bohr

• Electrons can olnly be certain distances away from nucleus (distance corresponds with energy level)
• Farthest away highest energy
• Closest, lowest energy

Quantum

Chadwick

• Said Rutherford only accounted for only half the mass of the nucleus
• Proved the presence of nuetrons in the nucleus

Milikan

Electron

• Negative charge
• Orbit around nucleus
• Mass so low its neglected

Proton

• Positivley charged
• located in nucleus
• mass = 1 amu

Nuetron

• Neutrally charged
• Located in nucleus
• mass = 1 amu

Empty Space Concept

• The space around the nucleus is empty
• Electrons orbit in this space

Nucleus

• Central portion of an atom
• made of protons and neutrons

Atomic Number

• The number of protons

Isotopes

• elements with the same atomic number but different mass
• Atomic mass is the isotopes averaged

Ground State

• Electrons at the lowest energy level
• Closest to nucleus

Excited State

• Highest energy level
• Unstable condition
• have absorbed heat

Dual Nature of Light

• Frequency and wavelength are inversley related
• Frequency increases, wavelength decreases

Particle Nature

• Shine light on matter it will conduct heat
• Electrons DO move

Photons

• Packets of energy
• behave like particles

Frequency

• Cycles per second

Amplitude

• Bright or intense amount of light

Continuous Spectra

• Wavelengths (colors) Fade from one to another across the complete spectra

Bright Line Spectra

• Spectrum that only contains certain wavelengths

When light strikes and electron

• electron moves to higher energy level then goes back down
• This creates bright line spectra

Quanta

• The amount of energy required to excite an electron to the highest energy level

Heisenburg's Uncertainty Principle

Orbital

Principle Quantum Number

• Each principle energy level consists of one or more sublevels
• n = main energy level (1,2,3,4)

Sublevel

• Can have one or more
• S, P, D, F

Valence Electrons

• All electrons in the outermost energy level

Kernal

• The nucleus and all non-valence electrons

Electron Configurations

• 3D orbital is higher than 4S

1s< 2s< 2p< 3s< 3p< 3d< 4s< 3d< 4p...

Ion

• An atom that has gained or lost an electron
• Atom is no longer nuetral

Anion

• negative ion
• Atom has gained and electron

Cation

• Postive Ion
• Atom has lost and electron

Electron Dot Notation

• The symbol and dots that show the type of atom and the valence electrons

Ionic Radius

• The measure of the size of the atoms ion in a crystal lattace

Ionization Energy

• The energy required to remove the most loosely held electron from an atom

Electron Affinity

• The energy change that occurs when an atom gains an electron

Electronegravity

• A property of an element that indicates how strongly an atom attracts electrons (chemical bond)