Atomic Structure, Mass Numbers, Isotopes, and Ions

Fundamental Atomic Structure and Subatomic Particles

  • Atom Architecture:

    • Atoms consist of a central nucleus surrounded by orbiting electrons.

    • Protons: Located inside the central nucleus; possess a positive electrical charge.

    • Neutrons: Located inside the central nucleus; possess no electrical charge (neutral).

    • Electrons: Orbit the central nucleus; possess a negative electrical charge.

  • Electrical Neutrality of Atoms:

    • Atoms have no overall electrical charge.

    • Neutrality occurs because the number of electrons orbiting the nucleus is exactly equal to the number of protons contained within the nucleus.

    • The positive charges of the protons are fully canceled out by the negative charges of the electrons.

Determining Protons, Neutrons, and Electrons in Elements

  • Periodic Table Notation:

    • Chemical symbols on the periodic table are displayed with two distinct numbers.

    • Atomic Number:

      • The smaller number associated with an element symbol.

      • Represents the exact number of protons in the nucleus of an atom.

      • Determines the number of electrons in a neutral atom, as electron count equals proton count.

      • Every single atom of a specific element possesses the exact same number of protons.

    • Mass Number:

      • The larger number associated with an element symbol.

      • Represents the combined total count of protons and neutrons added together within the nucleus.

  • Mathematical Formula for Subatomic Particle Calculations:

    • Number of Protons=Atomic Number\text{Number of Protons} = \text{Atomic Number}

    • Number of Electrons=Atomic Number(for neutral atoms)\text{Number of Electrons} = \text{Atomic Number} \quad (\text{for neutral atoms})

    • Number of Neutrons=Mass Number−Atomic Number\text{Number of Neutrons} = \text{Mass Number} - \text{Atomic Number}

Subatomic Particle Calculations for Specific Neutral Elements

  • Lithium (Li\text{Li}):

    • Atomic Number = 33

    • Mass Number = 77

    • Protons = 33

    • Electrons = 33

    • Neutrons = 7−3=47 - 3 = 4

  • Beryllium (Be\text{Be}):

    • Protons = 44

    • Electrons = 44

    • Neutrons = 55

  • Sodium (Na\text{Na}):

    • Protons = 1111

    • Electrons = 1111

    • Neutrons = 1212

  • Fluorine (F\text{F}):

    • Protons = 99

    • Electrons = 99

    • Neutrons = 1010

  • Phosphorus (P\text{P}):

    • Protons = 1515

    • Electrons = 1515

    • Neutrons = 1616

Isotopes

  • Definition:

    • Isotopes are atoms of the same element that contain the same number of protons but different numbers of neutrons.

  • Key Principles:

    • The number of protons defines the identity of an element and is fixed for all atoms of that element.

    • The number of neutrons in an atom is not fixed and can vary among individual atoms of the same element.

  • Isotopes of Carbon:

    • Carbon Isotope 1 (Carbon-12): Contains 66 protons and 66 neutrons.

    • Carbon Isotope 2 (Carbon-13): Contains 66 protons and 77 neutrons.

    • Carbon Isotope 3 (Carbon-14): Contains 66 protons and 88 neutrons.

  • Isotopes of Chlorine:

    • Chlorine Isotope 1 (Chlorine-35): Contains 1717 protons and 1818 neutrons.

    • Chlorine Isotope 2 (Chlorine-37): Contains 1717 protons and 2020 neutrons.

Ions and Electrical Charges

  • Definition:

    • Ions are atoms (or groups of atoms) that have an overall electrical charge because they have lost or gained electrons.

  • Mechanism of Charge Formation:

    • Electrons carry a negative charge; therefore, changing electron count changes the overall charge while proton count remains unchanged.

    • Positive Ions (Cations): Formed when an atom loses electrons (fewer negative charges than positive protons).

    • Negative Ions (Anions): Formed when an atom gains electrons (more negative charges than positive protons).

  • Subatomic Calculations for Specific Ions:

    • Sodium Ion (Na+\text{Na}^+):

      • Overall charge: Single positive charge (+1+1

      • Mechanism: Lost 11 electron.

      • Protons = 1111

      • Neutrons = 1212

      • Electrons = 11−1=1011 - 1 = 10

    • Fluoride Ion (F−\text{F}^-):

      • Overall charge: Single negative charge (−1-1

      • Mechanism: Gained 11 electron.

      • Protons = 99

      • Neutrons = 1010

      • Electrons = 9+1=109 + 1 = 10

    • Oxide Ion (O2−\text{O}^{2-}):

      • Overall charge: Two negative charge (−2-2

      • Mechanism: Gained 22 electrons.

      • Protons = 88

      • Neutrons = 88

      • Electrons = 8+2=108 + 2 = 10

    • Aluminum Ion (Al3+\text{Al}^{3+}):

      • Overall charge: Three positive charge (+3+3

      • Mechanism: Lost 33 electrons.

      • Protons = 1313

      • Neutrons = 1414

      • Electrons = 13−3=1013 - 3 = 10