Atomic Structure and Electron Arrangement

Basics of Atomic Structure

• The higher the coefficient or shell, the higher the energy of an atom.
• The arrangement of electrons in an atom determines how it interacts with other atoms.
• The arrangement of electrons in each atom determines its physical properties.
• All orbitals in the same sublevel (e.g. 2s, 1s, 3p) have the same amount of energy.
• Mass Number = Protons + Neutrons, not shown on the periodic table.
• Atomic Number = Protons, shown as the large number on the periodic table.
• Average Atomic Mass = average mass of all isotopes of an element.

Principal Quantum Number

• Principal Quantum Number (N) describes the energy level and size of an orbital.
• As N increases, the energy and distance from the nucleus also increase.
• N can be any positive integer (1, 2, 3, 4, ...).
• Orbitals do not exist unless an electron is occupying it.
• Orbitals are the last shell level.

Periodic Table

• The periodic table is split into blocks, with rows corresponding to the coefficient in electron configuration.
• For the d block, the coefficient is one less than the row it is in.
• The exponent is the number of columns from the left of the start of the specific letter block.
• Students can explain the reasoning behind the organization of the periodic table.

Electron Configuration and Orbitals

• Students can construct the appropriate electron configuration and orbital diagram for a given element.
• Students can identify the alkali metals, alkaline earth metals, transitional metals, halogens, noble gases, metals, non-metals, and metalloids on the periodic table.

Vocabulary

• Isotope: a different version of an element with a different number of neutrons.
• Ground State: the lowest energy state of an atom or other particle.
• Electron Configuration: the distribution of electrons in an atom.
• Orbital: a region around the nucleus that can hold a specific number of electrons (s: 2, p: 6, d: 10, f: 14).
• Valence Electrons: electrons that are furthest from the nucleus and have the most energy.
• Protons: positively charged particles found in the nucleus.
• Neutrons: neutrally charged particles found in the nucleus.
• Electrons: negatively charged particles found around the nucleus.
• Nucleus: the center of the atom, positively charged, containing protons and neutrons.
• Electron Cloud: the area around the nucleus where there is a negative charge.

Principles/Laws

• Pauli Exclusion Principle: electrons in the same orbital must have a different spin.
• Hund's Rule: in a sublevel, all orbitals get one electron before pairing up.
• Aufbau Principle: fill orbitals from low energy to high energy (s → p).

Unit 7: Wave Types

• Radio Waves: much longer wavelength than visible light, used for communication.
• Microwave: used for cooking, heat application, and communication, similar to radio waves.
• Infrared: used for thermal imaging and remote controls.
• Ultraviolet: used for killing bacteria and creating fluorescent effects, but can damage cells.
• X-Ray: used for imaging, but can damage molecular structure and cause harm.
• Gamma Rays: used to treat cancer, but can damage the entire body.

Emissions Spectra

• Each element has a unique emission spectra.
• Emission spectra shows the colors of light emitted when an element is hit with the right wavelength needed to make a jump to a higher energy level.