Unit Two – Chemistry – Flashcards

Smallest partical of an element

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

• 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

• 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

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

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

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

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

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

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

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

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

• The number of protons

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

• Electrons at the lowest energy level
• Closest to nucleus

• Highest energy level
• Unstable condition
• have absorbed heat

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

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

• Packets of energy
• behave like particles

• Cycles per second

• Bright or intense amount of light

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

• Spectrum that only contains certain wavelengths

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

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

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

• Can have one or more
• S, P, D, F

• All electrons in the outermost energy level

• The nucleus and all non-valence electrons

• 3D orbital is higher than 4S

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

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

• negative ion
• Atom has gained and electron

• Postive Ion
• Atom has lost and electron

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

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

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

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

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