Atomic Structure and Models of the Atom
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Questions and Answers

Which subatomic particle has a negligible contribution to the overall mass of an atom?

  • Proton
  • Nucleon
  • Neutron
  • Electron (correct)

What term collectively refers to protons and neutrons within the atom's nucleus?

  • Electrons
  • Nucleons (correct)
  • Subatomic particles
  • Atomic mass units

According to Democritus, what are the fundamental properties of atoms?

  • Indivisible with no internal structure (correct)
  • Indivisible and composed of smaller particles
  • Divisible and containing internal structure
  • Divisible and in constant motion

What statement accurately reflects Democritus' theory of the universe?

<p>Atoms are mostly empty space. (A)</p> Signup and view all the answers

What role did John Dalton play in the development of atomic theory?

<p>He adapted Democritus's theory into the first modern atomic model. (D)</p> Signup and view all the answers

What is a key tenet of Dalton's atomic theory?

<p>Atoms are indestructible and unchangeable. (D)</p> Signup and view all the answers

In a stable, neutral atom, how does the number of protons compare to the number of electrons?

<p>The number of protons and electrons is equal. (A)</p> Signup and view all the answers

Which of the following statements accurately describes the charges of subatomic particles?

<p>Protons have a positive charge, electrons have a negative charge, and neutrons are neutral. (C)</p> Signup and view all the answers

If an atom has an atomic number of 15, how many protons does it have?

<p>15 (A)</p> Signup and view all the answers

An atom has an atomic mass of 40 and an atomic number of 20. How many neutrons does it have?

<p>20 (C)</p> Signup and view all the answers

What is the relationship between the number of protons and electrons in a neutral atom?

<p>Number of protons is equal to the number of electrons. (C)</p> Signup and view all the answers

Which of the following statements defines isotopes?

<p>Atoms with the same number of protons but different numbers of neutrons. (A)</p> Signup and view all the answers

An atom of potassium has an atomic mass of 39 and an atomic number of 19. What is the number of neutrons in this atom?

<p>20 (A)</p> Signup and view all the answers

If an element has 30 protons, what is its atomic number?

<p>30 (C)</p> Signup and view all the answers

An element has an atomic number of 8. How many electrons does a neutral atom of this element have?

<p>8 (C)</p> Signup and view all the answers

What distinguishes isotopes of the same element?

<p>Different number of neutrons (D)</p> Signup and view all the answers

Two isotopes of the same element will always have the same number of which subatomic particle?

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

Given an isotope with an atomic mass of 48 and 20 protons, what is the number of neutrons?

<p>28 (D)</p> Signup and view all the answers

How does the number of electrons compare to the number of protons in a positively charged ion?

<p>Fewer electrons than protons (A)</p> Signup and view all the answers

Which equation correctly calculates the number of neutrons in an atom?

<p>Number of Neutrons = Atomic Mass - Atomic Number (A)</p> Signup and view all the answers

What is the atomic mass of an oxygen isotope with 8 protons and 10 neutrons?

<p>18 (C)</p> Signup and view all the answers

If an atom gains an electron, what type of ion is formed?

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

Which subatomic particle most significantly affects the atomic mass of an atom?

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

Which of the following is true regarding the atomic number of isotopes of a given element?

<p>The atomic number is always the same. (C)</p> Signup and view all the answers

What did J.J. Thomson call the negatively-charged particles he discovered within the atom?

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

Which subatomic particles are found in the nucleus of an atom?

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

What was the key conclusion from Rutherford's gold foil experiment regarding the structure of an atom?

<p>Most of the mass and positive charge are concentrated in a small, dense nucleus. (A)</p> Signup and view all the answers

According to Thomson's plum pudding model, how is positive charge distributed within an atom?

<p>Evenly distributed throughout the atom. (A)</p> Signup and view all the answers

What type of particles were used to bombard gold foil in Rutherford's experiment?

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

What was a limitation of Thomson's atomic model?

<p>It did not predict the movement of electrons. (B)</p> Signup and view all the answers

Which scientist is credited with proposing the nuclear model of the atom?

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

According to Rutherford's model, how do electrons arrange themselves within atoms?

<p>Electrons circulate at some distance around the nucleus. (A)</p> Signup and view all the answers

What is the overall charge of an atom's nucleus?

<p>Positive, due to the presence of protons. (D)</p> Signup and view all the answers

What led to the discovery of subatomic particles in atoms?

<p>Experiments conducted from the late 19th to early 20th centuries. (B)</p> Signup and view all the answers

If two atoms have the same number of protons but a different number of neutrons, what are they classified as?

<p>Isotopes of the same element. (D)</p> Signup and view all the answers

What happens when you rub a plastic strip with a cloth, according to the information provided?

<p>The plastic strip becomes negatively charged as electrons move onto it. (D)</p> Signup and view all the answers

How did ancient Greek philosophers view atoms?

<p>As indivisible and without any parts. (C)</p> Signup and view all the answers

Which of the following best describes the behavior of like charges?

<p>They repel each other. (D)</p> Signup and view all the answers

Which statement accurately compares magnets and electric charges?

<p>Both magnets and electric charges exhibit similar interactions, where like entities repel, and opposites attract. (B)</p> Signup and view all the answers

An atom has 11 protons, 12 neutrons, and 11 electrons. What is the atom's charge?

<p>0 (C)</p> Signup and view all the answers

According to Bohr's atomic model, what determines the energy of an electron's orbit?

<p>The size of the orbit. (C)</p> Signup and view all the answers

What key concept from Heisenberg did Schrodinger apply to formulate his atomic model?

<p>The uncertainty principle. (D)</p> Signup and view all the answers

In the quantum mechanical model, what term describes the region with a high probability of containing electrons?

<p>Orbital. (B)</p> Signup and view all the answers

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

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

What information does the mass number of an atom provide?

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

According to Bohr's model, how do electrons move between energy levels?

<p>By instantly jumping between orbits when gaining or losing energy. (A)</p> Signup and view all the answers

How is an atomic symbol written when it consists of two letters?

<p>The first letter is capitalized, and the second is lowercase. (A)</p> Signup and view all the answers

What was the primary limitation of Rutherford's planetary model that Bohr addressed?

<p>It couldn't explain why electrons didn't collapse into the nucleus. (C)</p> Signup and view all the answers

Flashcards

Atom

The basic unit of matter, consisting of a nucleus and electrons.

Subatomic Particles

Particles that make up an atom: protons, neutrons, and electrons.

Proton

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

Neutron

An electrically neutral particle located in the atomic nucleus.

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Electron

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

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Electric Charge

A property of particles that causes them to experience a force in an electric field.

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Matter

Anything that has mass and occupies space, composed of atoms.

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Magnetic Charge Analogy

Similar to electric charges; like charges repel, unlike charges attract.

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Plum Pudding Model

Thomson's atomic model depicting electrons in a positive 'soup'.

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Rutherford's Experiment

Bombarded gold foil with alpha particles, revealing atomic structure.

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Nuclear Model of the Atom

Model proposed by Rutherford, featuring a dense nucleus with electrons orbiting.

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Dense Nucleus

The small, positively charged core of an atom containing most mass.

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Alpha Particles

Positively charged particles used in Rutherford's gold foil experiment.

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Atom Structure

Atoms consist of electrons in orbit around a dense nucleus.

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Thomson’s Key Points

The essential aspects of J.J. Thomson’s atomic model explained.

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Nucleus

The central part of an atom, containing protons and neutrons.

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Democritus

A Greek philosopher who first used the term 'atomos' to describe indivisible particles of matter.

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Dalton's Atomic Model

John Dalton's early model stating that all matter is made of atoms, which are indivisible and unchangeable.

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Nucleons

Collective term for protons and neutrons in the nucleus.

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Niels Bohr

A physicist who improved the planetary model of the atom.

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Planetary Model

An atomic model where electrons orbit the nucleus like planets.

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Energy Level

Specific orbits where electrons have distinct energy sizes.

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Quantum Mechanical Model

Modern atomic model describing electrons as a cloud rather than fixed orbits.

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Electron Cloud

Region surrounding the nucleus where electrons are likely found.

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Atomic Number

The number of protons in an atom, also equal to electrons in a neutral atom.

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Mass Number

Total number of protons and neutrons in an atom's nucleus.

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Atomic Symbol

One- or two-letter notation representing a specific element.

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Atomic Mass

The total number of protons and neutrons in an atom's nucleus.

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Isotopes

Atoms with the same number of protons but different numbers of neutrons.

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Neutron Calculation

Formula used to find the number of neutrons: atomic mass - atomic number.

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Chemical Properties of Isotopes

Isotopes share similar chemical behaviors but differ in physical properties due to mass.

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Number of Neutrons

Calculated as atomic mass minus atomic number.

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C-12

An isotope of carbon with 6 neutrons and an atomic mass of 12.

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C-13

An isotope of carbon with 7 neutrons and an atomic mass of 13.

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Ion

A charged atom or molecule due to unequal numbers of protons and electrons.

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Positive Ion

An atom with more protons than electrons, resulting in a positive charge.

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Negative Ion

An atom with more electrons than protons, resulting in a negative charge.

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Study Notes

Atomic Structure

  • Atoms are the basic units of matter
  • Atoms are composed of even smaller particles called subatomic particles (protons, neutrons, and electrons)
  • Protons have a positive charge.
  • Neutrons have no charge (neutral).
  • Electrons have a negative charge.
  • The nucleus is the dense central core of an atom containing protons and neutrons.
  • Electrons orbit the nucleus.
  • The mass of an atom comes from the protons and neutrons.
  • Collectively, the protons and neutrons are called nucleons
  • The nucleus is tightly packed with nucleons

Models of the Atom

  • Democritus (400 BC): First to propose the idea of the atom (atomos, meaning indivisible)

    • He thought matter could be divided until it could not be divided any further; this is the fundamental unit.
    • He also theorized all matter consists of atoms.
    • There is empty space between atoms;
    • Atoms have no internal structure; Atoms are completely solid.
    • Each atom of a different substance is different in size, weight and shape

  • John Dalton (1800s): Solid Sphere/ Billiard Ball Model -Atoms are indivisible (meaning they cannot be broken down further) and unchangeable -Elements are characterized by the weight of their atoms.

    • When elements react, it is their atoms that combine to form new compounds.

  • Joseph John Thomson (1890s): Plum Pudding Model/ Raisin bread Model

    • Atoms have negatively-charged electrons embedded within a positively charged substance.

  • Ernest Rutherford (1910s): Nuclear Model

    • Atoms have a dense, positively charged nucleus at the center.
    • Most of the atom is empty space.
    • Electrons orbit the nucleus.

  • Niels Bohr (1910s): Planetary Model

    • Electrons orbit the nucleus in paths or levels called energy shells with distinct fixed energy levels
    • Electrons reside in orbits; they move between each energy shell only when they gain and lose energy

  • Erwin Schrödinger (1920s): Quantum Mechanical Model/ Electron Cloud Model

    • Electrons do not orbit the nucleus in fixed paths.
    • Instead, they exist in regions of high probability called orbitals within specific energy levels
    • This model uses concepts of quantum mechanics to describe the electron behavior within an atom.

Determining the Number of Subatomic Particles

  • Atomic number = number of protons in the nucleus = number of electrons
  • Mass number = number of protons + number of neutrons
  • Number of neutrons = mass number - atomic number

Isotopes

  • Atoms of the same element but with different numbers of neutrons.
  • Isotopes have the same chemical properties
  • Isotopes differ in mass thus causing differences in their physical properties.

Ions

  • Charged atoms or molecules.
  • Ions are formed when an atom gains or loses electrons.
  • Gains electrons: negatively charged ions (anions)
  • Loses electrons: positively charged ions (cations)

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Science 8 Quarter 3 Lesson 3 Atoms: Inside Out PDF

Description

Explore the fundamentals of atomic structure and the various models that have been proposed throughout history. From the basic components of atoms to the theories of ancient philosophers like Democritus, this quiz covers key concepts and terminology related to atoms and their behavior.

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