Chemistry 2024

• Proton:

  • Positively charged subatomic particle found in the nucleus of an atom
  • Contributes to the atomic number of an element and defines its identity
  • Mass of approximately 1 atomic mass unit (amu) and a charge of +1
• Neutron:

  • Neutral subatomic particle found in the nucleus of an atom
  • Adds to the mass of the nucleus without affecting the element's identity
  • Mass of approximately 1 amu and no charge
• Electron:

  • Negatively charged subatomic particle found outside the nucleus in the electron cloud
  • Involved in chemical bonding and determines the atom's reactivity
  • Negligible mass compared to protons and neutrons
• Discovery of Subatomic Particles:

  • Protons: Discovered by Ernest Rutherford through his gold foil experiment in 1911
  • Neutrons: James Chadwick discovered neutrons in 1932 through experiments involving beryllium and paraffin
  • Electrons: J.J. Thomson discovered electrons in 1897 using a cathode ray tube experiment
• Mass Number:

  • Total number of protons and neutrons in the nucleus of an atom
• Atomic Number:

  • Number of protons in the nucleus of an atom, determining its chemical properties and identity
• Isotope:

  • Atoms of the same element with different numbers of neutrons
• Unstable nuclei release radiation to achieve stability
• Types of radiation:

  • Alpha (α), beta (β), and gamma (γ) emissions
• Alpha particles:

  • Helium nuclei (2 protons, 2 neutrons), emitted from heavy nuclei
• Beta particles:

  • Electrons (β-) or positrons (β+), emitted from neutron-rich or neutron-poor nuclei
• Gamma radiation:

  • High-energy electromagnetic radiation emitted during radioactive decay
• Radiation Equations:

  • Expressions describing the decay process of radioactive isotopes, categorized as alpha, beta, or gamma decay
• Half-Life:

  • Time required for half of the radioactive atoms in a sample to decay into stable daughter atoms
• Groups and Periods:

  • Vertical columns and horizontal rows on the periodic table, respectively
• Identification of Elements:

  • Alkali metals: Group 1 (Li, Na, K, Rb, Cs, Fr)
  • Alkaline earth metals: Group 2 (Be, Mg, Ca, Sr, Ba, Ra)
  • Halogens: Group 17 (F, Cl, Br, I, At)
  • Noble gases: Group 18 (He, Ne, Ar, Kr, Xe, Rn)
  • Transition metals: Groups 3-12 (Sc-Zn, Y-Cd, La-Hg, Ac-Cn)
• Electron Configuration:

  • Representation of the arrangement of electrons in an atom's energy levels
• Valence Electron:

  • Electrons in the outermost energy level of an atom, involved in bonding
• Noble Gas Electron Configuration:

  • Electron configuration resembling that of a noble gas, achieved by atoms to attain stability
• Formation of Ions:

  • Atoms gain or lose electrons to achieve a noble gas electron configuration, resulting in the formation of ions
• Transition Metal Charge:

  • Roman numerals denote the charge of transition metals in compounds, indicating the number of electrons lost or gained to achieve stability
• Ionic Bonding:

  • Bonding resulting from the transfer of electrons between atoms
• Covalent Bonding:

  • Bonding involving the sharing of electrons between atoms
• Simple Covalent Molecules:

  • CO2 (Carbon dioxide)
  • H2O (Water)
  • NH3 (Ammonia)
  • HCl (Hydrogen chloride)
  • O2 (Oxygen)
  • Cl2 (Chlorine)
  • N2 (Nitrogen)
  • H2 (Hydrogen)
• Atomic Structure Formula:

  • Atomic Structure = Protons + Neutrons + Electrons
• Mass Number Formula:

  • Mass Number = Protons + Neutrons
• Atomic Number Formula:

  • Atomic Number = Protons
• Isotope Definition:

  • Isotope = Element + Neutrons
• Radiation Decay Formula:

  • Parent Nucleus → Daughter Nucleus + Particle/Radiation
• Radiation Equations:

  • Alpha Decay Equation: Parent Nucleus → Daughter Nucleus + α
  • Beta Decay Equation: Parent Nucleus → Daughter Nucleus + β
  • Gamma Decay Equation: Excited Nucleus → Ground State Nucleus + γ
• Half-Life Definition and Graph Interpretation:

  • Half-Life Formula: t1/2 = 0.693λ
• Electron Configuration Formula:

  • Electron Configuration = 1s^2 2s^2 2p^6 (for example)
• Formation of Ions for Noble Gas Configuration:

  • Ion Charge Formula: Ion Charge = Number of Electrons Lost/Gained
• Transition Metal Charge Determination:

  • Total Positive Charge = Total Negative Charge
• Combining ions to form simple ionic compounds:

  • Ionic Compound Formula: Cation + Anion = Compound
• Chemical Bonding Definitions:

  • Ionic Bonding Formula: Transfer of Electrons
  • Covalent Bonding Formula: Sharing of Electrons