Atoms & Elements
Q: What is the smallest building block of matter?
A: An atom
Q: Two or more atoms chemically bonded together form a…
A: Molecule
Q: The starting substances in a chemical reaction are called…
A: Reactants
Q: During a chemical reaction, atoms are never…
A: Created or destroyed
Q: A reaction that absorbs heat is called…
A: Endothermic
Q: What chart organizes all known elements?
A: Periodic table
Q: Salt crystals forming repeating patterns are what type of structure?
A: Extended structure
Q: What forms after a chemical reaction happens?
A: Products
Q: What must happen to atoms during a chemical reaction?
A: They rearrange
Q: A reaction that releases heat is called…
A: Exothermic
Q: What does the atomic number tell you?
A: Number of protons
Q: What holds atoms together in molecules?
A: Chemical bonds
Q: What law states that matter cannot be created or destroyed?
A: Law of Conservation of Matter
Q: If CH₄ reacts with O₂, the atoms in CH₄ must also appear where?
A: In the products
Q: If temperature decreases during a reaction, it is likely what type?
A: Endothermic
Q: An element is a substance made of only one type of what?
A: Atom
Q: A water molecule (H₂O) has how many atoms total?
A: 3 atoms
Q: Color change, gas formation, or temperature change are signs of what?
A: Chemical reaction
Q: Why must chemical equations be balanced?
A: To follow the law of conservation of matter
Q: Fireworks releasing heat and light are what type of reaction?
A: Exothermic
Q: What do we call the total number of protons + neutrons?
A: Atomic mass
Q: Why do extended structures have predictable properties?
A: Atoms repeat in a regular pattern
Q: In a chemical equation, what does the arrow mean?
A: “Yields” or “produces”
Q: H₂ + O → H₂O is NOT balanced. How many oxygen atoms are missing on the left?
A: One more oxygen atom needed (should be O₂)
Q: Why can chemical reactions either absorb or release energy?
A: Breaking and forming bonds requires different amounts of energy