Dalton's atomic theory/atomic models Flashcards
Dalton’s Atomic Theory
All elements are composed of tiny indivisible particles called atoms. Atoms of the same element are identical. Atoms of different elements can physically/chemically combine in simple whole-number ratios to form compounds. A chemical reaction is a rearrangement of atoms.
Democritus
reasoned that atoms were indivisible and indestructible
J. J. Thompson
Came up with the ‘plum pudding’ model of the atom
Plum pudding
Model of the atom in which most of the atom is a positive substance, which has small negative ‘balls’ of charge ‘floating’ in it.
Gold Foil Experiment
What was the experiment that showed that most of the atom is made up of empty space, with a positive charge at the center and electrons moving around it?
Planetary or Bohr model
Which model of the atom has a nucleus containing protons (and later neutrons) with electrons orbiting them in ‘orbitals’ but able to move from one orbital to another by absorbing or emitting energy?
Quantum
Model of the atom in which the nucleus contains both protons and neutrons, and the electrons exist in ‘shells’ around the nucleus. It is impossible to know both the location and velocity of an atom at the same time, so the shells are regions of probability.
electron
first particle to be discovered
A negatively charged particle that is found outside the nucleus of an atom
proton
second particle to be discovered
Positively charged particle in the nucleus of an atom
neutron
third particle to be discovered
a neutral subatomic particle in the nucleus of an atom
spectroscopy
When atoms absorb energy, their electrons can move to a higher energy level. When that energy is emitted, the electrons move back to a lower energy level. The sets of amounts of energy that can be absorbed or emitted by atoms of a specific element are used to identify them in a process known as___________________
Rutherford
Performed the gold foil experiment
Niels Bohr
Came up with the planetary model
Inference
Something you assume based on information gathered by your senses
Observation
A statement about the natural world, usually made using one of the five senses
Fact
Observations about the natural world (many combined)
Theory
well-tested explanation that unifies a broad range of observations. (Tells you why a phenomenon occurs)
Conclusion
final judgment or decision reached by analysis of research or experimentation. Often states whether or not a hypothesis was supported
Controlled variable
the variable(s) which are kept the same between different trials. Something which might affect the outcome of a trial if it differed, but which is not being tested
Dependent variable
What you are measuring, the ‘effect’ of your independent variable, the recorded result of your experiment
Element
substance consisting entirely of one type of atom, with a specific number of protons and unique properties
Mass
the amount of matter in an object
Nucleus
the tiny, dense central portion of an atom, composed of protons and neutrons
Mass number
the total number of protons and neutrons in the nucleus of an atom (specific)
Atomic Number
The number of protons in the nucleus of an atom
Cation
A positively charged ion
Isotopes
Atoms of the same element that have different numbers of neutrons
Ion
A charged atom
Law
a statement, often mathematical, that describes a recurring observed phenomenon (Tells you how/what occurs)
Atomic Mass
The weighted average of the masses of all of the isotopes of an element (general)
Independent Varible
The variable which changes between trials, what you are comparing, what you believe will be the cause of a measurable difference between trials
Charge
A measure of the extra positive or negative particles that an object has.
Anion
A negatively charged ion
Atom
The smallest particle of an element
