Chapter 4: Atom Structure, Theories, and Experiments

What are atoms?

The smallest peice of an elements that still reatians the proeprties of that element, the smallest building block of matter

Who was Democritus and what did he do?

"Guy who named the atom after the greek word ""indivisible"" and made the discontinous theory of matter

Who made the law of conservation of mass and when?

Antione Lavoisier, 1770s

What does the law of conservation of mass say about atoms?

The mass of chemicals before the reactions equaled the mass of chemicals after the reaction.

Who made the law of definite proportions and when?

Joseph Proust (french), 1779

What does the law of defenite proportions of mass say?

The proportions of masses of chemicals in reactions is always the same.
Ex: 8g O + 1 g H = 9 g H₂o; 16g O + 2 g H = 18 g H₂o

Who made the law of multiple proportions and when?

John dalton (english), 1803

What does the law of multiple proportions say?

"The mass of one element combines with masses of other elements in simple, whole # ratios.

Law of definite proportions simple

the right number of pieces in the equation

Law of multiple proportions simple

the correct pieces in the equation

What is dalton's atomic theory (founded by putting together all 3 laws from earlier) and which are wrong? (put asterik)

1. Atoms are indivisible (not destroyed). 2. Atoms of the same element are identical. 3. Atoms combine in simple whole # ratios to form compounds. 4. Chemical reactions are the result of separating or combining atoms. 5. All matter is made up of atoms

Why are these rules wrong?

1. Atoms are indivisible (not destroyed) *
2. Atoms of the same element are identical * 1. Nuclear reactions can occur

What did william crookes do?

"Did experiments and named the ""glow"" cathode rays

What did JJ Thomson (english) do?

He took some of crookes idea's and then did a set if new experiments with cathod rays, discovered the electron in 1887

What is the charge of an electron

-1.602 x 10^-19

What is the mass of an electron?

9.11 x 10^-28

Explain everything that happened in the rutherford gold experiment

Positive alpha particles from Poloniuim (in the lead box) were released towards a thin sheet of gold foil. Most of the particles went through the foil and fizzed on the detector screen, but some, lik 1 in 20,000 particles, bounced back.

What conclusions were drawn from the rutherford gold experiment? what did it generally help to discover?

1. Positive portion of the atoms are in the middle 2. Most of the atom is empty. 3. Most of the mass comes from the middle. 4. Electrons orbit the nucleus; It helped to discover the nucleus of the atom

What is the location of a proton?

Nucleus

What is the location of a neutron?

nucleus

What is the location of an electron?

Orbit the nucleus

What is the charge of a proton?

positive

What is the charge of a neutron?

neutral

What is the charge of an electron?

negative

What is the relative mass of a proton?

1 amu

What is the relative mass of a neutron?

1 amu and a little more

What is the relative mass of an electron?

1/1837 amu (0.005 amu)

The proton determines the ____ of an atom.

identity

The neutron determines the ____ of an atom.

mass

The electron determines the ___ of an atom.

charge

What are quarks?

Particles that make up protons and neutrons

What are the 6 types of quarks?

Ups, downs, beauty, truth, charmed, strange

How much charge does an up quark hold?

+2/3 charge

How much charge does a down quark hold?

-1/3 charge

How many ups and downs make a proton?

2 ups, (4/3), 1 down (-1/3)

How many ups and downs make a neutron?

2 downs (-2/3), 1 up (2/3)

What are particle accelerators?

Miles long magnets propel particles along the chamber. The particles smash into eachother at high speeds. This results in nuclear asintegration

What are other examples of small particles (smaller than subatomic particles)?

Baryons, mesons, leptons, and omega particles

Who discovered the proton?

Golstein

Who discovered the neutron?

Chadwick

What are nucleons?

Particles that make up the nucleus

How many grams does a proton weigh?

1.67 x 10^-24

How many grams does a neutron weigh?

1.67 x 10^-24

What is the mass of a proton?

1 amu

What is the mass of a neutron?

Slightly more than 1 amu

What are isotopes? *

Different versions of the same element with different weights due to different numbers of neutrons

What is the abundance of protium?

99.985%

What is the abundance of deuterium?

0.015%

What is the abundance of tritium?

0%

How many subatomic particles does protium have and what are they?

1: 1 proton

How many subatomic particles does deuterium have and what are they?

2 - one proton and one neutron

How many subatomic particles does tritium have and what are they?

3 - 1 is a proton and 2 are neutrons

What is the relative mass of protium?

about 1 amu

What is the relative mass of deuterium?

2 amu

What is the relative mass of tritium?

3 amu

What is atomic mass?

The average mass of all of the isotopes of an element - is a number with a decimal, the largest number in an element box on the periodic table

What is atomic number?

Number of protons in the nucleus

What is mass number?

Sum of protons and nuetrons in a nucleus - rounded from atomic mass

What is the formula for finding atomic mass?

Average atomic mass (x̄) = (%)(mass of first isotope) + (%)(mass of second isotope)

What is a mass spectrometer?

A machine used to detect, analyze, and identify unknown chemcials

How does the mass spec work?

The samples put in are vaporized, bombarded with electrons, (in order to create + cations), and then they're placed in electrical magnetic fields

How does the mass spec calcualte what kind of sample it is?

Differences in neutrons (mass) make the paths of molecules different, and then they curve based on their mass. Heavier particles curve less