Introduction to the Atom (English)
PassChem: Sponholtz Productions・25 minutes read
Atoms consist of protons, neutrons, and electrons, with the atomic number indicating the number of protons and defining an element. Electrons, residing outside the nucleus, affect the charge of an atom, with specific rules governing their arrangement in orbitals.
Insights
- The atomic number of an element represents the number of protons it contains, defining its unique identity, while isotopes have the same number of protons but differ in the number of neutrons, affecting the mass number and atomic mass.
- Electrons, with a negative charge, reside outside the nucleus in orbitals, following specific rules for arrangement within an atom, such as the Poly Exclusion Principle and H's Rule, with orbitals of different shapes representing various energy levels.
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What are atoms made of?
Atoms are composed of protons, neutrons, and electrons.
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Summary
00:00
Understanding Atoms: Protons, Neutrons, Electrons, Isotopes
- Atoms are composed of protons, neutrons, and electrons, with the goal of determining the number of each in an atom.
- The atomic number indicates the number of protons in an atom, defining its elemental identity.
- Protons and neutrons are found in the nucleus, with neutrons acting as nuclear glue to hold protons together.
- Isotopes have the same number of protons but different numbers of neutrons, affecting the mass number.
- The atomic mass of an element is the weighted average of the masses of its isotopes.
- Electrons, negatively charged, reside outside the nucleus in orbitals, affecting the charge of an atom.
- An atom with an equal number of protons and electrons is neutral, while an ion has a charge due to an imbalance.
- The size comparison of protons, neutrons, and electrons within an atom is significant, with electrons residing in orbitals.
- Orbitals are three-dimensional regions where electrons are likely to be found, with different shapes representing different energy levels.
- Electron configurations follow specific rules to determine the arrangement of electrons in an atom's orbitals.
18:02
Electron Orbital Filling Rules and Examples
- Electrons are added to the lowest energy orbital first, then work up in relative energy: 1s, 2s, 2p, 3s, 3p, and so on.
- Poly Exclusion Principle: Only two electrons per orbital with opposite spin.
- H's Rule: Orbitals of equal energy are occupied by one electron before any orbital is occupied by a second electron.
- Example problem: Consult the periodic table to find the number of electrons in a neutral atom of carbon (6 electrons).
- Example problem: Find a home for 10 electrons in a neutral atom of fluorine (atomic number 9).
- Example problem: Find a home for 18 electrons in a neutral atom of calcium (atomic number 20).
- Example problem: Find a home for 31 electrons in a neutral atom of gallium (atomic number 31).
- Order of orbital filling obtained from the periodic table: 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, and so on.
- Abbreviated electron configurations combine inner Noble core electrons with outermost electrons.
