Atoms and Molecules
The center of an atom, where protons and neutrons are located, is called the ____.
Nucleus
Name the three main states of matter.
solid, liquid, and gas
Cutting a piece of paper in half is an example of a ____ change.
Physical
What is the chemical symbol for water?
H2O
I am the element found in water, and I have the chemical symbol "O". What element am I?
Oxygen
This is a substance made of two or more elements chemically combined in a fixed ratio. An example is water (H₂O). What is it called?
A compound
When a liquid turns into a gas, this process is called ____.
Evaporation
Burning a piece of paper produces ash, smoke, and new gases. This type of change is classified as a ____.
chemical change
This metal is found in bananas and has the symbol "K".
What is potassium?
I am a metal used in wiring and have the chemical symbol "Cu". What element am I?
Copper
If the number of protons in an atom is equal to the number of electrons it is a _____ atom.
neutral
What state of matter has particles that are spaced far apart and move freely?
Gas
Name one sign that a chemical change has occurred.
Any of the following: color change, production of gas/bubbles, temperature change, formation of a precipitate, change in smell)?
How many elements are on the periodic table?
118
I am a poisonous, yellow-green gas used in swimming pools to kill bacteria. My chemical symbol is "Cl". What element am I?
Chlorine
Name the three main subatomic particles in an atom and identify which one is the heaviest.
What are protons, neutrons, and electrons? (Neutrons are the heaviest.)
This state of matter has a definite volume but takes the shape of its container. The particles are close together but can move past each other. What state of matter is it?
Liquid
Name the natural example of a chemical reaction that happens in plants and produces oxygen.
Photosynthesis
The element with the symbol "Na" is commonly found in what everyday substance?
What is salt (sodium chloride or NaCl)?
I am the most abundant gas in Earth's atmosphere. What element am I?
Nitrogen
This type of substance is made by physically combining two or more materials, but each material keeps its own properties. It can be separated by physical means. What is it called?
What is a mixture?
The process of a solid changing directly into a gas is called ____.
Sublimation
In a chemical reaction, the mass of the products is always equal to the mass of the reactants. This principle is known as the law of ____.
Who invented the Periodic Table?
Dmitri Mendeleev
I am the only metal that is a liquid at room temperature. What element am I?
What is Mercury