🌟 8th Grade Science Final Study Guide 🌟

🟩 ELEMENTS


  • Q: What is a pure substance made of only one kind of atom?
    A: Element

  • Q: What does the atomic number represent?
    A: The number of protons in an atom

  • Q: What is the chemical symbol for an element?
    A: A 1- or 2-letter abbreviation (like H for Hydrogen)

  • Q: If two atoms have different numbers of protons, they are different…?
    A: Elements

  • Q: Which subatomic particle defines the element and never changes?
    A: Proton





🟦 COMPOUNDS & MOLECULES


  • Q: What do you call a group of two or more atoms bonded together?
    A: Molecule

  • Q: What is a molecule made of different elements?
    A: Compound

  • Q: What shows the number and type of elements in a molecule?
    A: Chemical formula

  • Q: How many hydrogen atoms are in H₂O?
    A: 2

  • Q: True or false: All compounds are molecules, but not all molecules are compounds.
    A: True





🟨 PERIODIC TABLE


  • Q: How are elements organized in the periodic table?
    A: By atomic number

  • Q: What are the rows of the periodic table called?
    A: Periods

  • Q: Elements in the same group have similar…?
    A: Chemical properties

  • Q: Which elements have properties of both metals and nonmetals?
    A: Metalloids

  • Q: Name the element groups: Group 1, 2, 17, 18
    A: Alkali metals, alkaline earth metals, halogens, noble gases





🟪 ATOMIC STRUCTURE


  • Q: What does the atomic number tell you?
    A: Number of protons

  • Q: Atomic mass = protons + ?
    A: Neutrons

  • Q: Atoms of the same element with different neutrons are called…?
    A: Isotopes

  • Q: Which electrons determine how reactive an atom is?
    A: Valence electrons

  • Q: If an atom has 11 protons and 12 neutrons, what’s its atomic mass?
    A: 23





🟥 CHEMICAL BONDS


  • Q: Why do atoms form bonds?
    A: To become more stable

  • Q: What type of bond shares electrons?
    A: Covalent bond

  • Q: What type of bond transfers electrons?
    A: Ionic bond

  • Q: What kind of bond is formed when sodium gives an electron to chlorine?
    A: Ionic bond

  • Q: What type of bond holds water together?
    A: Covalent bond





💥 FINAL JEOPARDY


  • Q: Who created the periodic table?
    A: Dmitri Mendeleev