2. Atoms & Elements

Rutherford Gold Foil Experiment

Observations and Conclusions of  Rutherford’s α (Alpha) Particle Scattering Experiment

Rutherford's atom  and the Gold Foil Experiment

Rutherford Gold Foil Oil Experiment

Use the mass spectrum of mercury to estimate the atomic mass 
of mercury. Estimate the masses and percent intensity values 
from the graph to three significant figures.

Use the data from the mass spectrum of a sample of an element to calculate the element’s atomic weight. Identify the element.

 most alpha particles passed through with little or no deflection. 

 a few alpha particles were deflected, some through large angles. 

 Rutherford proved that the plum-pudding model was incorrect. 

 alpha particles were directed at a thin sheet of gold foil. 

 In this experiment, the alpha particles were used as probes to study the structure of gold atoms. 

The atomic mass of fluorine is 18.998 amu, and its mass spectrum
shows a large peak at this mass. The atomic mass of chlorine
is 35.45 amu, yet the mass spectrum of chlorine does not
show a peak at this mass. Explain the difference.

Rutherford’s Experiment: Nuclear atom

Refer to Figure 2.10 showing a schematic illustration of a mass spectrometer.
(a) What is the purpose of bombarding the gaseous atoms with an electron beam?

Discovering which of the three subatomic particles proved to be
the most difficult—the proton, neutron, or electron? Why?

Refer to Figure 2.10 showing a schematic illustration of a mass spectrometer.
(b) Compare two ions with a +1 charge traveling through the curved, evacuated tube in the mass spectrometer. Will a heavier ion or lighter ion be deflected to a greater degree by the magnetic field?

Use the mass spectrum of rubidium to determine the atomic
mass of rubidium.
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/48ea8fa0a9a687d5-1659718848338.jpg" alt="" />

Use the mass spectrum of europium to determine the atomic
mass of europium.

The Gold Foil Experiment helped to disprove Thomson's Plum Pudding Model of the atom.

Rutherford's Model of an Atom | Structure of an Atom | Atomic Structure

Mass spectrometry is more often applied to molecules 
than to atoms. We will see in Chapter 3 that the molecular 
weight of a molecule is the sum of the atomic weights of the 
atoms in the molecule. The mass spectrum of H2 is taken 
under conditions that prevent decomposition into H atoms. 
The two naturally occurring isotopes of hydrogen 
are 1H (atomic mass = 1.00783 u; abundance 99.9885%) 
and 2H 1atomic mass = 2.01410 u; abundance 0.0115%2. 
(c) Which peak will be the largest, and which the smallest?

Prior to Rutherford’s gold foil experi-ment, the “plum pudding” model of the atom represented atomic structure. In this model, the atom is composed of elec-trons interspersed within a positive cloud of charge. If this were the correct model of the atom, predict how the results of Rutherford’s experiment would have been different. 
(a) The alpha particles would pass right through the gold foil with little to no deflection.
(b) Most of the alpha particles would be deflected back toward the source.
(c) Most of the alpha particles would be absorbed by the atom and neither pass through nor be deflected from the gold foil.

Rutherford’s Atomic Model - Part 1 | Atoms and Molecules | Don't Memorise

Rutherford's Gold Foil Experiment - Quick and Simple!

Rutherford Gold Foil Oil Experiment Example 2

There are two different isotopes of bromine atoms. Under
normal conditions, elemental bromine consists of Br2 molecules,
and the mass of a Br2 molecule is the sum of the masses
of the two atoms in the molecule. The mass spectrum of Br2
consists of three peaks:
Mass (u) Relative Size
157.836 0.2569
159.834 0.4999
161.832 0.2431
(e) Calculate the abundances of the two isotopes.
Calculate the abundance of the heavier isotope.

Consider the mass spectrometer shown in Figure 2.11. Determine
whether each of the following statements is true or false.
If false, correct the statement to make it true: (a) The paths
of neutral (uncharged) atoms are not affected by the magnet.

What discovery about atomic structure was made from the results of Rutherford’s gold foil experiment?

Which statements are inconsistent with Rutherford’s nuclear theory as it was originally stated? Why?
a. Since electrons are smaller than protons, and since a hydrogen atom contains only one proton and one electron, it must follow that the volume of a hydrogen atom is mostly due to the proton.
b. A nitrogen atom has 7 protons in its nucleus and 7 electrons outside of its nucleus.
c. A phosphorus atom has 15 protons in its nucleus and 150 electrons outside of its nucleus.
d. The majority of the mass of a fluorine atom is due to its 9 electrons.

Mass spectrometry is more often applied to molecules
than to atoms. We will see in Chapter 3 that the molecular
weight of a molecule is the sum of the atomic weights of the
atoms in the molecule. The mass spectrum of H2 is taken
under conditions that prevent decomposition into H atoms.
The two naturally occurring isotopes of hydrogen
are 1H (atomic mass = 1.00783 u; abundance 99.9885%)
and 2H 1atomic mass = 2.01410 u; abundance 0.0115%2.
(a) How many peaks will the mass spectrum have?

There are two different isotopes of bromine atoms. Under 
normal conditions, elemental bromine consists of Br2 molecules, 
and the mass of a Br2 molecule is the sum of the masses 
of the two atoms in the molecule. The mass spectrum of Br2 
consists of three peaks: 
Mass (u) Relative Size 
157.836 0.2569 
159.834 0.4999 
161.832 0.2431 
(c) Determine the average molecular mass of a Br2 molecule.

There are two different isotopes of bromine atoms. Under
normal conditions, elemental bromine consists of Br2 molecules,
and the mass of a Br2 molecule is the sum of the masses
of the two atoms in the molecule. The mass spectrum of Br2
consists of three peaks:
Mass (u) Relative Size
157.836 0.2569
159.834 0.4999
161.832 0.2431
(a) What is the origin of second (mass of 159.834 amu) peak (of what isotopes does each consist)?

Discovery of the Nucleus: Rutherford's Gold Foil Experiment

Bromine has two naturally occurring isotopes; 79Br (mass of 78.918) and 81Br (mass of 80.916). If the atomic weight of bromine is 79.904, predict the mass spectrum of a sample of bromine atoms. (LO 2.17)
(a) <img src="" alt="" />
(b) <img src="" alt="" />
(c) <img src="" alt="" />
(d) <img src="" alt="" />

Dorado Learning | K12 Sample Content | Rutherford's nuclear model of atom part1

Use the mass spectrum of lead to estimate the atomic mass of
lead. Estimate the mass and percent intensity values from the
graph to three significant figures.
<img src="https://lightcat-files.s3.amazonaws.com/problem_images/21033d4c00e4363c-1659949868116.jpg" alt="" />

What Did Rutherford's Gold Foil Experiment Show?

Rutherford’s Gold Foil Experiment

It is common in mass spectrometry to assume that the mass
of a cation is the same as that of its parent atom. (b) What percentage of the mass of an 1H
atom does the electron represent?

Rutherford Gold Foil Oil Experiment Example 1

What fraction of the a particles in Rutherford’s gold foil experiment
are scattered at large angles? Assume the gold foil
is two layers thick, as shown in Figure 2.9, and that the approximate
diameters of a gold atom and its nucleus are 270
pm and 1.0 * 10–2 pm, respectively. Hint: Calculate the cross
sectional area occupied by the nucleus as a fraction of that
occupied by the atom. Assume that the gold nuclei in each
layer are offset from each other.

Which statements are consistent with Rutherford’s nuclear theory as it was originally stated? Why?
a. The volume of an atom is mostly empty space.
b. The nucleus of an atom is small compared to the size of the atom.
c. Neutral lithium atoms contain more neutrons than protons.
d. Neutral lithium atoms contain more protons than electrons.

The natural abundance of 3He is 0.000137%. 
(c) Based on your 
answer to part (b), what would need to be the precision of a 
mass spectrometer that is able to differentiate between peaks 
that are due to 3He+ and 3H+?

Consider the mass spectrometer shown in Figure 2.11. Determine 
whether each of the following statements is true or false. 
If false, correct the statement to make it true: (b) The height of each peak in the mass spectrum is inversely 
proportional to the mass of that isotope.

The molecular weight of ethylene glycol is 62.0689 when calculated using the atomic weights found in a standard periodic table, yet the molecular weight determined experimentally by high-resolution mass spectrometry is 62.0368. Explain the discrepancy.

Learn the toughest concepts covered in Chemistry with step-by-step video tutorials and practice problems by world-class tutors

Jules

General Chemistry

https://static.studychannel.pearsonprd.tech/courses/general-chemistry/thumbnails/general-chemistry

#FFFFFF

Pearson

The Organic Chemistry Tutor

Don't Memorise

Dorado Learning

Chemin10

Physics4students

Tyler DeWitt

Jules Bruno

Studynlearn

PhysicsHigh

1. Intro to General Chemistry

3. Chemical Reactions

4. BONUS: Lab Techniques and Procedures

5. BONUS: Mathematical Operations and Functions

6. Chemical Quantities & Aqueous Reactions

7. Gases

8. Thermochemistry

9. Quantum Mechanics

10. Periodic Properties of the Elements

11. Bonding & Molecular Structure

12. Molecular Shapes & Valence Bond Theory

13. Liquids, Solids & Intermolecular Forces

14. Solutions

15. Chemical Kinetics

16. Chemical Equilibrium

17. Acid and Base Equilibrium

18. Aqueous Equilibrium

19. Chemical Thermodynamics

20. Electrochemistry

21. Nuclear Chemistry

22. Organic Chemistry

23. Chemistry of the Nonmetals

24. Transition Metals and Coordination Compounds

[BOOK CHEM] Clutch Version

Millikan Oil Drop Experiment

The Oil Drop Experiment helped with determining the fundamental charge of the electron.&nbsp;

Ions

Ions represent elements that possess either a positive charge or a negative charge.&nbsp;

Periodic Table: Charges

Elements lose or gain electrons to have the ideal number of outer shell electrons like the noble gases.&nbsp;

Law of Definite Proportions

"Different samples of a pure chemical compound always contain the same proportions of elements by mass."

Periodic Table: Classifications

The Periodic Table contains 3 Major Classifications when describing its elements

Isotopes

Isotopes are atoms of an element that have the same atomic number, but different mass number.&nbsp;

The Atom

The atom represents the basic functional unit in chemistry

Mole Concept

The Mole Concept involves the interconversions between different unit amounts of a substance.

Periodic Table: Representative Elements & Transition Metals

The Groups of the Periodic Table can be broken down into the Representative Elements and Transition Metals

Atomic Theory

John Dalton, one of the "Fathers of Chemistry"is credited with modernizing the Atomic Theory.

Subatomic Particles

The atom is composed of 3 subatomic particles:neutrons, protons, and electrons.

Periodic Table: Elemental Forms

The elements of the Periodic Table exist in different elemental forms in the natural world

Periodic Table: Phases

Under standard conditions of temperature and pressure, the elements can exist as solids, liquids or gases

Atomic Mass

The atomic mass of an element includes the masses of all 3 subatomic particles of neutrons, protons and electrons.&nbsp;

Periodic Table: Group Names

The Periodic Table can be further classified into Periods and Groups.&nbsp;

Law of Conservation of Mass

"In a chemical reaction, no matter is created or destroyed, but instead changes form."

Calculating Molar Mass

Molar Mass is a physical property that represents the mass of a substance divided by the amount of that substance.

The Gold Foil Experiment helped with the discovery of the positively charged nucleus.

Law of Multiple Proportions

“When 2 elements (A &amp; B) form different compounds, the mass of Element B that combine with 1 g of A are a ratio of whole numbers."

Periodic Table: Element Symbols

The Element Symbols of the Periodic Table represent the abbreviated form of an element