science chapter 4: studying atoms
Unlock all answers in this set
Unlock answersquestion
-All matter consists of small particles that cannot be divided -Atoms: from greek word atoms meaning indivisible
answer
Democritus
question
-All matter made up of earth, air, fire and water -fire: hot/dry -water: cold/wet -No limit to the number of times you could divide the matter
answer
Aristotle
question
-English, 18th century -studied behavior of gases in air -Determined that compounds have a fixed composition
answer
John Dalton
question
-All atoms of the same element have the same mass, atoms of different elements have different mass -compounds contain atoms of more than one element Atoms in compounds always combine in the same ratio ***THIS THEORY HAS BEEN ALTERED TODAY
answer
Dalton's Theory
question
English -when some materials are rubbed they attract other materials -these materials have a +/- charge -some charged particles can flow from one place to another (electric current) - he used a cathode ray tube (+and - metal at each end) and one outside the tube - A beam of electrons always bent toward + plate
answer
Thomson
question
- Atoms are made of smaller particles - Plum Pudding a positive mass with negative charges scattered out. The + and - cancel each other out
answer
Thomson's Model
question
- U gives off fast moving + particles - Directed a student, Marsden, to shoot them at a sheet of gold
answer
Rutherford's Theory
question
- When A particles were shot at gold sheet, most went right through - some were deflected slightly - some bounced right back
answer
Gold Foil Experiment
question
Dense center with a + charge - atom is mostly empty space
answer
Rutherford's Model
question
- PROTONS: found in nucleus; +1 charge, mass = 1 atomic mass unit (amu) - ELECTRONS: found outside nucleus, -1 charge, mass = 1/1863 amu (use 0) - NEUTRONS: discovered by chadwich, mass = 1 amu, o charge found in nucleus -protons and neutrons found in nucleus, electrons travel outside nucleus
answer
Subatomic Particles
question
number of protons in nucleus, also = number of electrons in an atom
answer
Atomic number
question
number of protons + number of neutrons in the nucleus; number of neutrons = mass number of - atoms number
answer
Mass number
question
atoms of the same element that have the same atomic number but different mass number (same # of protons, different # of neutrons)
answer
isotopes
question
Danish scientist - Nucleus surrounded by electrons - Model similar to solar system
answer
Bohr's Model
question
-Areas around the nucleus where electrons ove - Electrons can move from levels to level be gaining or losing energy - When energy is lost, it may be seen as light
answer
Enemy Levels
question
- Volume occupied by electrons - Cloud is denser where there are more electrons
answer
Electron Cloud Model
question
- Division of the cloud subdivision of energy levels - Place where electron is expected to be found -# of orbitals in every level = (#of level)
answer
Atomic Oritals
question
- Arrangement of electrons in the orbital - The most stable arrangement has electrons in the lowest energy levels (ground state) - When electrons are excited, they jump out to higher levels (excited state)
answer
Electron Configurations
