NEU Gen Chem 1 9/14-9/17 Toher

Until when was Dalton’s atomic theory accepted as true?
His theory was considered valid for a majority of the 19th century after he proposed it.
What experiment is JJ Thomson remembered for?

He performed the cathode ray tube experiment.

What does Coulomb’s Law state?
Opposite charges attract while similar charges repel each other.
What is the equation of Coulomb’s Law and what do the components stand for?

F=(kq1q2)/d2 (force equals a constant times charge 1 times charge 2 all over distance squared)

After his experiment, what did Thompson discover?

He discovered both the mass and charge of the electron.

Explain what is meant by the “plumb pudding” model of the atom

The model states that an atom is comprised of a positively-charged “dough” with negatively charged electrons scattered throughout the positive dough.

What experiment did Robert Millikan perform?

He performed the oil drop experiment.

What did JJ Thomson discover?

He discovered both the presence of the electron and its mass/charge ratio (but not the individual components of the ratio).

What did Millikan’s experiment find?
His oil drop experiment found not only the charge of the electron but he also found the mass.
What experiment is Ernest Rutherford remembered for?

He is noted for his gold foil experiment.

What did Rutherford’s experiment show?

His experiment showed the presence of the atomic nucleus as a central + charged region of the atom.

What was the major draw-back of Rutherford’s experiment?

He accounted for the charge of the nucleus but failed to incorporate its mass.

What did James Chadwick discover?

He discovered that in addition to positively charged particles that the nucleus also contains neutral particles.

Give the letter abrieviations for atomic number, atomic mass and charge.

atomic number = z, atomic mass = a and charge = q.

In nuclear notation where do atomic number, mass and charge all go?

Atomic number is noted at the bottom left, atomic mass at the top left and charge is noted at the top right of the given chemical symbol.

Define ion

An ion is a charged particle resulting from a gain/loss of electrons.

Define cation

A cation is a positively charged ion resulting from electron deficit.

Define anion

An anion is a negatively charged ion resulting from electron surplus.

True or false: no matter what the charge of an atom its proton-electron ratio will always be 1:1

False. Only neutrally-charged atoms have a 1:1 ratio of protons and electrons.

What does oxidation refer to?

Oxidation refers to the loss of electrons.

What do the electrons of metals tend to do and what do they form as a result?

They tend to lose electrons to make cations.

What do the electrons of non-metals tend to do and what do they form?

They tend to gain electrons to form anions.

Define isotope

Isotopes are representative particles of the same element which differ by their number of neutrons in the nucleus.

Out of z, q and a which ones can and can’t change?
A;and q can change while z can’t.
What does mass spectomotry do?

It provides a distribution plot of each isotope of which an element is comprised and the isotopes relative percent composition.

Define amu

amu stands for atomic mass unit; one amu is equal to 1/12 the mass of Carbon-12.

How do you determine average atomic mass?

Average atomic mass is the percent of isotopic abundance multiplied by the isotope’s amu’s.

Define physical properties.

Physical properties are observable characteristics of a substance when stable.

Give some examples of physical properties.

Physical properties include (but are not limited to) luster, malleableness (bending ability), ductility (ability to be pulled into a wire), odor, conductivity (both electrical and thermal), taste, density and physical state change temperatures.

Define physical change.

Physical change is defined as the transformation from one stage /phase of matter into another (gas to liquid, liquid to solid, etc.).

Challenge: what is the physical change of going from a gas to a solid called?
Going from a gas to a solid is called deposition.
Define chemical change

A chemical change is defined as one or more substances transforming into one or more different substances with different physical properties.

Give some examples of indicators that a chemical reaction has occured.

Chemical reactions typically involve some sort of temperature change (both endo- and exothermacism), evolution of a gas, solid precipitation upon mixing 2 or more aqueous substances and color change.

Define precipitate

A precipitate is define as any insoluable solid formed from 2 clear solutions.

Define units

Units describe how much of something there is.

Challenge: what is one liter equal to?
A liter is equal to a decameter cubed (1L=1dm3).
Define the metric system

The metric system is a uniform system of prefixes and pre-determined base units for measurements. The prefixes tell us which power of 10 is assigned to a base unit.

What should be known for unit conversions before performing the actual conversion?

The correct conversion factor should either be given or known (such as 1 inch = 2.54 centimeters)

Give the mathematical formula to perform a unit conversion

First you divide the desired unit by the given unit. Then you multiply the result by the given unit.

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