CEM 141:Chapter 1 Atoms
-"Particles" emerged from one disc(the cathode) and moved to the other(the anode)
-These particles could be deflected by electrical fields in a direction that would indicate they
were negatively charged
-(the particles could also be deflected by magnetic fields)
-The particles carried the electrical charge (-) that is if the ray was bent for example by a
magnetic field the charge went with it
-The metal that the cathode was made of did not affect the behavior of the ray- so whatever the
composition of the ray it appeared to be independent of the element that it came from -
ANS-Thompson's Experiment showed:
-Atoms not to be cut
-Elements:Earth, Fire, Air, and Water
-Atoms were thought to be in constant motion- based on watching the movement of specks of
dust in sunlight and that there was nothing or a "void" between them (later called the Brownian
Motion)
-Atoms of different elements had different shapes and sizes.
-Believed that the shape of atoms determined their properties - ANS-Greeks
-Atoms was mostly empty space(Greeks said this)
-Small dense positive nucleus in the center of the atom - ANS-Rutherford's experiment showed:
-Discovered in 1932
-Harder to detect (Why?) Neutral in charge, not manipulated with electric and magnetic fields
-Reside in the nucleus
-Slightly heavier than protons
-The last thing to be discovered - ANS-Neutrons
-Energy associated with the position of a system of objects in a field.
-You can't have PE without a field (gravitational, electric, magnetic)
-You can't have PE without two or more objects (in the field) - ANS-Potential Energy
-The energy associated with motion
-If the objects speeds up the KE increases - ANS-Kinetic Energy
1.Claim(the target of your explanation)
2.Evidence (the data or scientific principle you are using to support your claim)
3.Reasoning (how the evidence support the claim) - ANS-Constructing a Scientific Explanation
1.Gravity
2.Electromagnetic
, 3.Strong
4.Weak - ANS-The Four Fundamental Types of Forces
1/2(mv)^2 - ANS-KE=
2 or more - ANS-How many objects do gravitational fields require?
2 or more atoms bonded together - ANS-Molecule=
91 (or 98) - ANS-How many elements are naturally occurring?
A ball is falling down toward the ground
Two positively charged objects move apart - ANS-In which of the following situations does the
PE of the system decrease?
A law describes the phenomenon(tells you what). A theory explains the phenomenon(tells you
why). - ANS-What is the difference between Law and Theory?
about 0.1nanometer (1*10^-9) - ANS-How big do you think an atom (H) is?
Air and smoke - ANS-Which of the following contains atoms, air, light, smoke, and heat?
An alpha particle has two protons and two neutrons. It is the nucleus of a helium atom -
ANS-What is an alpha particle?
an interaction - ANS-What is a force?
atomic or molecular level - ANS-Gravitational forces are too weak to be detected at the?
Because the force of gravity is equal to the electromagnetic force - ANS-Why can we stand on
Earth?
Because the gravitational interaction between the Earth and the ball - ANS-Here is Katie again
the ball is falling down. What causes to potential energy to decrease?
can be a drawing or graph or a diagram or an equation, physical,mental - ANS-Scientific Model
Cathodes made of multiple different metals emit electrons - ANS-Dalton's atomic theory
proposed that atoms are invisible. Which piece of evidence forced a revision of this model of the
atom?
causes atoms to be attracted to each other (the electrons will react with each other first) -
ANS-LDFs
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