Isotopes and Atomic Mass
22 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to Lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What does Bohr's model of the atom describe regarding electron behavior?

  • Electrons can exist in random orbits around the nucleus.
  • Electrons are stationary and do not move at all.
  • Electrons can jump between specified orbitals, gaining or losing energy. (correct)
  • Electrons emit radiation continuously as they revolve around the nucleus.

Which postulate is NOT part of Dalton's atomic theory?

  • In a compound, atoms of different elements always combine in the same way.
  • Atoms of the same element are identical.
  • Atoms of different elements can be identical in every respect. (correct)
  • Matter is composed of small invisible particles called atoms.

What medieval practice aimed to transform metals into gold and contributed to the scientific revolution?

  • Alchemy and Astrology
  • Astrology
  • Alchemy (correct)
  • Physics

According to Bohr's theory, when does an electron emit radiation?

<p>When it jumps from one orbital to another. (C)</p> Signup and view all the answers

Which of the following individuals is known for experimenting with dissolving metals in acid during the alchemy period?

<p>Daniel Sennert (D)</p> Signup and view all the answers

What defines isotopes of the same element?

<p>Same atomic number but different mass numbers. (C)</p> Signup and view all the answers

Which part of the isotopic notation represents the number of protons?

<p>Z (D)</p> Signup and view all the answers

What is the atomic mass of Carbon-12?

<p>12 amu (A)</p> Signup and view all the answers

Which isotope of hydrogen has two additional neutrons?

<p>Tritium (A)</p> Signup and view all the answers

How is the isotope notation for a neutral uranium atom with 146 neutrons expressed?

<p>238 U 92 (B)</p> Signup and view all the answers

How many protons does Carbon-14 contain?

<p>6 (C)</p> Signup and view all the answers

What is true about the atomic mass of Carbon?

<p>It is an average of the isotopes' masses. (B)</p> Signup and view all the answers

The equation (14.0031)(X)+(15.0001)(1-X)=14.0067 is used to calculate what?

<p>The percent abundance of nitrogen isotopes. (C)</p> Signup and view all the answers

Who discovered the positively charged particle in an atom?

<p>Ernest Rutherford (B)</p> Signup and view all the answers

What was a key observation of Rutherford's gold foil experiment?

<p>Some alpha particles bounced back. (D)</p> Signup and view all the answers

Which particle was discovered by James Chadwick?

<p>Neutron (A)</p> Signup and view all the answers

What does the atomic number (Z) of an element represent?

<p>The number of protons in the nucleus (A)</p> Signup and view all the answers

What is the primary conflict between Rutherford's model and Maxwell's theory?

<p>Electrons would spiral into the nucleus due to energy loss. (B)</p> Signup and view all the answers

Which scientist was noted for the development of the periodic table in relation to atomic number?

<p>Henry Moseley (B)</p> Signup and view all the answers

What is a characteristic feature of an atom as described in the models discussed?

<p>Atoms are mostly empty space with electrons orbiting a nucleus. (C)</p> Signup and view all the answers

What happens to the charge of an atom if it gains electrons?

<p>The atom becomes negatively charged. (D)</p> Signup and view all the answers

Signup and view all the answers

Flashcards

Isotopes

Atoms of the same element that have the same atomic number (number of protons) but different mass numbers (number of protons and neutrons).

Isotope Notation

A notation used to represent isotopes, including the element symbol, atomic number, mass number, and charge.

Mass Number (A)

The sum of the number of protons and neutrons in an atom's nucleus, represented by the symbol 'A'.

Atomic Number (Z)

The number of protons in an atom's nucleus. It defines the element and is represented by the symbol 'Z'.

Signup and view all the flashcards

Atomic Charge (E)

The difference between the number of protons and electrons in an atom. It determines the atom's charge and is represented by the symbol 'E'.

Signup and view all the flashcards

Atomic Mass

The average relative atomic mass of all the isotopes of an element, taking into account their abundance.

Signup and view all the flashcards

Isotopic Abundance

The relative abundance of each isotope of an element in nature.

Signup and view all the flashcards

Isotope Separation

A process that uses the difference in mass between isotopes to separate them. This is useful for separating isotopes with different applications, such as uranium isotopes for nuclear energy.

Signup and view all the flashcards

Quantum Concept

A foundational principle in physics stating that certain quantities, like energy levels of electrons, are quantized - they exist in discrete values, not continuous ones.

Signup and view all the flashcards

Bohr's Model

Bohr modified Rutherford's model by incorporating the quantum concept, suggesting that electrons exist in specific orbits with fixed energy levels.

Signup and view all the flashcards

Quantum Leap

The process where an electron jumps between different energy levels in an atom, gaining or losing energy in the process.

Signup and view all the flashcards

Law of Conservation of Mass

A fundamental law of nature stating that mass remains constant during chemical reactions, meaning it cannot be created or destroyed.

Signup and view all the flashcards

Law of Definite Proportion

A law stating that a given chemical compound always contains the same elements in the same proportion by mass, regardless of its source or method of preparation.

Signup and view all the flashcards

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Signup and view all the flashcards

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Signup and view all the flashcards

Neutron

A neutral subatomic particle found in the nucleus of an atom.

Signup and view all the flashcards

Thomson's Atomic Model

The model proposed by J.J. Thomson that suggested that atoms are a sphere of positive charge with negatively charged electrons embedded in it.

Signup and view all the flashcards

Rutherford's Atomic Model

The model proposed by Ernest Rutherford that suggested a small, dense, positively charged nucleus with electrons orbiting around it.

Signup and view all the flashcards

Rutherford's Gold Foil Experiment

An experiment conducted by Rutherford to test Thomson's model, where alpha particles were fired at a thin gold foil.

Signup and view all the flashcards

Ion

An atom that has gained or lost one or more electrons, resulting in a net positive or negative charge.

Signup and view all the flashcards

Study Notes

Isotopes

  • Atoms of the same element with the same atomic number (Z) but different mass numbers (A)
  • Identified using isotopic notation (XAZ) where:
    • X = element symbol
    • A = mass number (protons + neutrons)
    • Z = atomic number (number of protons)
  • Isotopes are distinguished by their neutron count
  • Neutral atoms have equal number of protons and electrons (E=0)
  • Isotope notation can also be written as element name/symbol-mass number (e.g., uranium-238 or U-238)

Isotopes and Mass Numbers

  • Hydrogen has the simplest nucleus (one proton)
  • Atomic mass of hydrogen is approximately 1.008 amu.
  • Some hydrogen isotopes have additional neutrons:
    • Deuterium (one additional neutron), atomic mass ≈ 2.014 amu
    • Tritium (two additional neutrons), atomic mass ≈ 3.016 amu
  • Deuterium and tritium are isotopes of hydrogen, but behave similarly chemically to normal hydrogen.

Atomic Mass and Isotopic Abundance

  • Carbon has three isotopes: Carbon-12, Carbon-13, and Carbon-14
  • Carbon-12 is the most common and lightest.
    • Six protons
    • Six electrons
    • Six neutrons
  • Carbon-13 is of medium weight
    • Six protons
    • Six electrons
    • Seven neutrons
  • Carbon-14 is the rarest and heaviest among the carbon isotopes.
    • Six protons
    • Six electrons
    • Eight neutrons

Development of Atomic Structure

  • Eugen Goldstein: Discovered positively charged subatomic particles (protons) in anode rays.
  • Ernest Rutherford: Coined the term "proton"
  • J.J. Thomson: Discovered electrons
  • James Chadwick: Discovered neutrons

The Plum Pudding Model

  • Thomson's model of the atom depicted electrons embedded in a sphere of positive charge, like plums in a pudding.

Rutherford's Gold Foil Experiment

  • Verified Thomson's model
  • Alpha particles were directed at a thin gold foil
  • Most particles passed straight through
  • Some particles were deflected at large angles
  • A few particles bounced back
  • This indicated a concentrated positive charge (nucleus) within the atom, surrounded by electrons.

Atomic Models

  • Similarities and differences between Thomson and Rutherford's models: Thomson proposed a theory, compared an atom to a watermelon, and stated that electrons reside within a positively charged sphere. Rutherford conducted an experiment, stating electrons moved around a central nucleus.
  • Modern atomic model: Atom is mostly empty space with a nucleus containing protons and neutrons, with electrons orbiting the nucleus.

Modern Periodic Table

  • Henry Moseley: Determined the atomic number corresponds to the number of protons in an atom.
  • James Maxwell: Explained that the loss of energy by moving charged particles may produce radiation and affect atom stability.

Laws of Chemistry

  • Law of Conservation of Mass: Total mass of substances before a reaction equals the total mass after the reaction.
  • Law of Definite Proportions: Elements combine in fixed proportions to form a compound

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Quiz Team

Related Documents

Isotope PDF

Description

Explore the fascinating world of isotopes in this quiz, which covers definitions, notation, and various isotopes of elements like hydrogen and carbon. Test your understanding of atomic mass and isotopic abundance, and learn to distinguish between different isotopes based on their neutron count.

More Like This

Isotopes and Atomic Mass Quiz
5 questions

Average Atomic Mass Quiz: Isotopes Explained

BestPerformingSerendipity avatar
BestPerformingSerendipity
Chemistry: Atomic Mass and Isotopes Quiz
11 questions

Chemistry: Atomic Mass and Isotopes Quiz

AudibleWonder avatar
AudibleWonder
Chemistry Quiz: Isotopes and Atomic Mass
37 questions

Chemistry Quiz: Isotopes and Atomic Mass

FeatureRichBamboo1998 avatar
FeatureRichBamboo1998
Chemistry Isotopes and Atomic Mass
8 questions

Chemistry Isotopes and Atomic Mass

FantasticSelenite4815 avatar
FantasticSelenite4815
Use Quizgecko on...
Browser
Open
Browser
Browser