Ch 5: Understanding Atomic Structure: Homework Help

1. The Atom

The physical basis that everything is composed of is called matter and the smallest unit of matter is called an atom. Learn about the atom, subatomic particles, the nucleus, elements, and the periodic table.

2. Atomic Number and Mass Number

An atom is defined as the smallest particle of an element that displays the same properties of that element. Learn about the main components of an atom (protons, neutrons, & electrons), the characteristics of each component, and how to determine the atomic number and the mass number of an atom.

3. Early Atomic Theory: Dalton, Thomson, Rutherford and Millikan

The current knowledge of atoms and atomic theory has been informed by many scientists going back to Aristotle and Democritus. Learn about the contributions made to early atomic theory by scientists working in more recent times, such as Dalton, Thomson, Rutherford, and Millikan.

4. Isotopes and Average Atomic Mass

Isotopes are variations of the same element with differing numbers of neutrons and, subsequently, different atomic masses. Learn how scientists consider isotopes when they calculate average atomic mass.

5. Avogadro's Number: Using the Mole to Count Atoms

Atoms are microscopic and challenging to count as a result. Learn about the importance of understanding the mole, which is simply a large number or quantity of something, also known as Avogadro's number, and how it helps scientists count large numbers of atoms.

6. Electron Configurations in Atomic Energy Levels

Electron configuration is the representation of how the electrons in an atom are arranged, which can be used to predict the properties of an element. Learn about patterns of energy levels in elements on the periodic table, how to identify the number of electrons in a neutral atom, and how to write an electron configuration for neutral atoms.

7. Hund's Rule, the Pauli Exclusion Principle & the Aufbau Principle

Three rules that help define electron positions within an atom are Hund's Rule, the Pauli exclusion principle, and the Aufbau principle. Discover how these inform quantum physics, the arrangement of electrons, and the order in which shells and sub shells are occupied.

8. Diamagnetism & Paramagnetism: Definition & Explanation

Diamagnetism and paramagnetism are important concepts in understanding atomic structure. Learn about electron configuration, and then learn about diamagnetism and paramagnetism and how these differ from one another.

9. Four Quantum Numbers: Principal, Angular Momentum, Magnetic & Spin

Quantum numbers describe specific properties of an electron. Learn about atomic orbital, the four quantum numbers (principal, angular momentum, magnetic, and spin), and how to write quantum numbers based on electron configuration.

10. The Bohr Model and Atomic Spectra

The Bohr model of the atom established the existence of a positive nucleus surrounded by electrons in specific energy levels. As electrons move from higher-energy to lower-energy levels, energy in the atom is released in the form of photons. Learn about the Bohr Model, atomic spectra, and how electrons emit different colors of light.

11. Atomic Radius: Definition, Formula & Example

The atomic radius is simply half the diameter of the atom itself, but is not as intuitive as it may seem, as an increase of atomic mass does not always correspond with a larger radius or size. Explore these nuances by learning to calculate the formula behind atomic radii.

12. Heisenberg Uncertainty Principle: Definition & Equation

A core concept in quantum mechanics is known as the Heisenberg uncertainty principle. Learn more about the uncertainty principle and about Werner Karl Heisenberg, the physicist who developed the principle. Also, learn the equation for the Heisenberg uncertainty principle.

13. The de Broglie Hypothesis: Definition & Significance

The de Broglie hypothesis proposes that matter can exhibit both wave and particle behavior. Learn more about the implications of the de Broglie hypothesis and how to derive the equation, which actually is a combination of two others by Albert Einstein and another physicist.