Chemistry 4

Max Planck

-6.626 x 10-34 J s is this scientist constant. -Photoelectric effect. -Energy=constant x frequency. -Energy id released in small, specific (discrete) packets (amounts) called "quanta". -No model.

Niels Bohr

-Electrons travel about the nucleus and fixed energy levels (orbits). -The further the orbit is from the nucleus the higher the energy. -He did his research using hydrogen.

Democritus

-First person to think of the idea of the atom -theorized that atoms are indestructible and indivisible -atom" comes from greek word "indivisible" -Model is the sphere.

Madame Curie

-First person to use the term radioactivity to referred to emission of particles coming from certain elements like uranium. -Determined that radioactivity was coming from the center of the atom. -She has no atomic model.

James Chadwick

-He discovered another particle in the nucleus of the atom= neutron. -no model

Enrico Fermi

-He discovered that when neutrons are produced in the splitting of uranium the neutrons might continue to split other uranium atoms -process starts a chain reaction releasing an enormous amount of energy first atomic pile later created for self-sustaining nuclear chain reaction -no model?

Ernest Rutherford

-Person found nucleus determined that the nucleus was positively charged, discovered protons concluded that most of the atom was completely empty space. -Experiment: Gold foil. -The jimmy neutron model.

John Dalton

-Scientist to theorized that all elements are composed of tiny indivisible particles called atoms. -Atoms of the same element are identical. -The atoms of any one are different from those of any other element. -Atoms of different elements can physically mix together or can chemically combine in simple whole- number ratios to form compounds. -Chemical reactions occur when atoms are separated form each other, joined or rearranged in different combinations. -Atoms of one element are never changed into atoms of another element by chemical reactions. -Model is the sphere.

Louis de Broglie

-Suppose that matter electron specifically have a dual nature. -Electrons can act as both particles and waves. -Model rainbow wave with a nucleus in the center.

JJ Thomson

-This scientist used cathode rays to discover the negatively charges particle called electrons. -Model is the plum pudding model or chocolate chip model. -Circle with ( + )with( - )around it

Werner Heisenberg

-Uncertainty principle= it is impossible to know both of the velocity and the position of an electron the same time -no model?

Erwin Schrodinger

-Use theoretical calculations to determine the location of electrons. -His mathematical equation describes the probability of finding an electron in an area of space. -His model is known as the cloud model.

Robert Millikan

-Using the oil drop experiment he calculated the mass and charge of the electron. -No model.

Which of argon's three isotopes is most abundant: argon-36, argon-38, or argon-40? (Hint: the atomic mass of argon is 39.948 amu.)

Argon-40

What is the difference between the mass number and the atomic number of the atom?

Atomic mass is the total weight and the atomic number is the amount of protons.

How is atomic number different from mass number?

Atomic number is the number of protons in an atom. Mass number is the number of protons + neutrons in an atom.

Isotopes

Atoms of the same element that have the same atomic number but different atomic masses due to a different number of neutrons

How do the isotopes of a given element differ from one another?

Different mass numbers and different numbers of neutrons.

Name two ways that isotopes of an element differ.

Different number of electrons they are ions and different number of neutrons they are isotopes.

Dalton's atomic theory

First theory to relate chemical changes to events at the atomic level

What does the number represent in the isotope platinum-194?

Mass number

What equation tells you how to calculate the number of neutrons in an atom?

Mass number-atomic number= neutrons

Electron

Negatively charged subatomic particle

What is the mass number of an element?

Number of protons + number of neutrons=(round atomic mass)

Atomic number

Number of protons in the nucleus of an atom of an element

What is the atomic number and what does it tell you?

Number of protons in the nucleus of an element.

Proton

Positively charge subatomic particle found in the nucleus of an atom

Why is an atom electrically neutral?

Protons and electrons cancel each other out.

Determine the number of electrons, protons, and neutrons in an atom.

Protons and electrons is the atomic number. Mass number-atomic number=neutrons.

What is the composition of the nucleus?

Protons and neutrons

Do you know the charge on each of the subatomic particles found in the atom?

Protons- positive Neutrons- neutral Electrons- negative

Would you expect two electrons to attract or repel each other?

Repel because they are negative charges.

Neutron

Subatomic particle with no charge in a mass of 1 amu; found in the nucleus of an atom

Where are the electrons?

Surround the nucleus

The atomic masses of elements are generally not whole numbers. Explain why.

The elements have different isotopes. The atomic mass is the average of all the isotopes of the element that exist.

Nucleus

Tiny,dense central portion of an atom composed of protons and neutrons

Atomic mass

Weighted average of the masses of the isotopes of an element

How is average atomic mass calculated? What does it mean by "weighted average atomic mass"?

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What is an atomic mass unit, can you explain it? What is meant by relative atomic mass, relative to what?

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How is atomic mass calculated?

mass of each isotope x natural abundance + products

How do the charge and mass of a neutron compare to the charge and mass of a proton?

A neutron has no charge and a proton has a positive charge. A neutron has a relative mass of 1 and a proton has a relative mass of +1.

Cathode ray

A stream of electrons produced at the negative electrode of a tube containing a gas at low pressure

Atomic mass unit

A unit of mass equal to one-twelfth the mass of a carbon-12 atom

What is the atomic mass of an element?

A weighted average of mass of the atoms in a naturally occurring sample of the element.

How many proton are in the nuclei of the following atoms? A. Phosphorus (P) B. Molybdenum (Mo) C. Aluminum (Al) D. Cadmium (Cd) E. Chromium (Cr) F. Lead (Pb)

A. 15 B. 42 C. 14 D. 48 E. 24 F. 82

What does the atomic number of each atom represent?

The number of protons in the atom.

What distinguishes the atoms of one element from the atoms of another?

The number of protons.

Atom

The smallest particle of an element thast retains its idenity in a chemical reaction

Mass number

total number of protons and neutrons in the nucleus of an atom

Designate isotopes and determine the number of electrons, protons, and neutrons using those forms of designation.

~Hyphen Notation Element's name-mass # Carbon-12 ~Nuclear Symbol Mass# >Element's Symbol Atomic# 12 C 6