Atomic Structure & Element
What is the term for the number of protons in an atom that determines the element's identity?
What is the atomic number?
How does the structure of a molecule affect its properties?
The type and arrangement of atoms in a molecule determine its properties. For example, the arrangement of carbon atoms in diamond makes it hard, while in graphite it makes it soft.
What is the key difference between a physical and chemical property?
What is a physical property can be observed without changing the substance’s identity, while a chemical property involves a substance changing into a new substance.
Why do scientists use models of atoms and molecules?
What is because atoms and molecules are too small to be seen directly, so models help visualize and understand their structure and behavior?
What type of change occurs when a solid turns into a liquid, like ice melting?
What is a physical change?
What property of an element makes it unique and different from all other elements?
What is the number of protons (atomic number)?
What is the difference between an element and a compound?
An element consists of only one type of atom, while a compound is made of two or more different types of atoms chemically bonded together.
What physical property would you use to identify an unknown metal that could help distinguish it from others?
What is density, melting point, or conductivity?
How can a model of a crystal help scientists understand its properties?
What is by showing how atoms are arranged in a repeating, orderly pattern, which affects the crystal’s shape and properties?
If a substance is heated and undergoes a chemical reaction that produces a new substance, what kind of change has occurred?
What is a chemical change (chemical reaction)?
Explain why two atoms of the same element will have the same chemical properties.
Atoms of the same element have the same number of protons, which defines the element’s chemical behavior and properties.
When a substance reacts with oxygen to form rust, this is an example of a ___ change.
What is a chemical change?
Explain why rusting is considered a chemical change and not a physical change.
What is because rusting involves a chemical reaction with oxygen, changing the composition of the original metal and forming a new substance?
What is an extended structure, and how does it relate to crystals?
What is an extended structure is a repeating arrangement of atoms, like in crystals, where atoms or molecules are connected in a regular, repeating pattern.
Give an example of a physical change that does not alter the identity of a substance.
What is water freezing, or metal being hammered into a thin sheet?
If you add heat to a solid and it turns directly into a gas without becoming a liquid, this process is called what?
What is sublimation?
This term describes a change where energy is either absorbed or released.
What is an energy change?
The ability of an object to conduct heat is a ____ property.
What is a physical property?
What is it called when a gas turns into a solid without going through the liquid phase?
What is deposition?
What are the signs that a chemical reaction has occurred?
What are changes in color, the appearance of a gas, formation of a precipitate, or the release of energy as light or heat?
Why can’t elements be broken down into simpler substances through chemical reactions?
What is because elements are pure substances made of only one type of atom, and there are no simpler components to break them down into?
Is the following reaction balanced or unbalanced?
What is unbalanced?
What’s an example of a chemical reaction where energy is released, and what is that energy called?
What is a combustion reaction (e.g., burning wood), and the energy released is thermal energy (heat) and light?
What is the significance of a fixed ratio in a compound like water (H₂O)?
What is the fixed ratio ensures that in any sample of water, there are always two hydrogen atoms for every one oxygen atom, maintaining consistent properties?
What happens to the mass of a substance during a chemical reaction?
What is it remains constant (law of conservation of mass)?