The Structure of Atoms
Using the Periodic Table
Types of Matter
Acids, Bases, Salts
Photosynthesis & Cellular Respiration
The Carbon Cycle and Law of Conservation
Unit One: Nature of Science
Unit Two: Intro to Matter
100
What are the three main subatomic particles in an atom?
Protons, neutrons, and electrons.
100
What does the atomic number of an element tell you?
The number of protons in the atom.
100
A substance made of only one type of atom or molecule is called what?
A pure substance.
100
On the pH scale, what type of substance has a pH below 7?
An acid.
100
What gas do plants take in for photosynthesis?
Carbon dioxide (CO₂).
100
What process uses sunlight, carbon dioxide, and water to produce glucose and release oxygen?
Photosynthesis.
100
This word describes an idea that can be tested with observations or experiments.
What is a hypothesis?
100
These particles are packed tightly together and only vibrate in place, giving this state of matter a definite shape and volume.
What is a solid?
200
Where are protons and neutrons located inside an atom?
In the nucleus.
200
Elements in the same group or family have what in common?
They have similar chemical and physical properties.
200
Salt water is clear and evenly mixed throughout. Is it a heterogeneous or homogeneous mixture?
A homogeneous mixture (solution).
200
What type of compound has a slippery feel and a bitter taste, and shows a pH above 7?
A base.
200
What cell organelle carries out photosynthesis?
The chloroplast.
200
What gas is released during cellular respiration?
Carbon dioxide (CO₂).
200
Scientists repeat an experiment many times to increase accuracy. When the same person does multiple trials, this is called what?
What is repetition?
200
In this state of matter, particles are close but can slide past each other, so it has a definite volume but takes the shape of its container.
What is a liquid?
300
An atom has 11 protons. Which element is it, and how many electrons does it have if it’s neutral?
Sodium (Na); it has 11 electrons.
300
Neon is a non-reactive gas. Based on its location on the periodic table, which other elements would have similar properties?
Other noble gases (He, Ar, Kr, Xe, Rn).
300
You boil a clear liquid and a white powder remains at the bottom. What does this tell you about the original substance?
It was a mixture (specifically a solution) because a dissolved solid was left behind.
300
Vinegar (acetic acid) reacts with baking soda (a base). What type of compound is produced when an acid and a base combine?
A salt (plus water).
300
Cellular respiration produces energy for the cell. What molecule is broken down during cellular respiration to release this energy?
Glucose (sugar).
300
Name one carbon reservoir that stores carbon for long periods of time.
Examples: Oceans, forests, soil, fossil fuels, limestone/sediment, atmosphere.
300
In an experiment testing how sunlight affects plant growth, sunlight is this type of variable.
What is the independent (tested) variable?
300
This is the ratio of an object’s mass to its volume and is what really determines if something will sink or float.
What is density?
400
What non-contact force keeps electrons moving around the nucleus instead of flying away?
The electrical force (attraction between protons and electrons).
400
As you move left to right across a period, why do the properties of elements change?
Because the number of protons increases, changing how strongly the nucleus attracts electrons, which affects element behavior.
400
What is the main difference between a compound and a mixture?
Compounds are chemically combined, forming new substances with new properties; mixtures are physically combined, and each substance keeps its original properties.
400
Lemon juice, bleach, and table salt are all compounds. Which one is a neutral compound, and why?
Table salt (NaCl) — it is formed from an acid and a base and does not act as an acid or base in water.
400
Why do plant cells need both chloroplasts and mitochondria?
Chloroplasts make glucose during photosynthesis, and mitochondria break down that glucose to release ATP energy during cellular respiration.
400
During photosynthesis, the number of carbon atoms before and after the process stays the same. Which scientific law does this demonstrate?
The Law of Conservation of Mass.
400
A class does an experiment once. Another class at a different school repeats the same experiment to see if they get similar results. This process is called what, and why is it important?
What is replication, and it is important to check if results are reliable/consistent?
400
On Earth, this quantity changes if you go to the top of a mountain, but this one stays the same because the amount of matter doesn’t change. Name both.
What is weight (changes) and mass (stays the same)?
500
Two forces act inside an atom: electrical force and strong nuclear force. Explain how each one helps keep the atom together.
Electrical force attracts electrons to the positively charged nucleus.
Strong nuclear force holds protons and neutrons tightly together in the nucleus.
500
Oxygen (O) and Bromine (Br) are not in the same group. Which one is more similar to Fluorine (F), and why?
Bromine (Br) — it is in the same group (Group 17), so it shares similar chemical properties.
500
Air is made of nitrogen, oxygen, carbon dioxide, and other gases evenly spread throughout. Why is air classified as a homogeneous mixture and not a compound?
Because the gases are not chemically bonded and are evenly mixed, each keeping its own properties — so it is a homogeneous mixture, not a compound.
500
A student tests three liquids:
Liquid A turns blue litmus paper red
Liquid B turns red litmus paper blue
Liquid C does not change either paper
Classify each liquid as acid, base, or neutral, and explain.
Liquid A: Acid — acids turn blue litmus red
Liquid B: Base — bases turn red litmus blue
Liquid C: Neutral — no color change indicates neutrality
500
Photosynthesis and cellular respiration are often described as “opposite processes.” Explain why.
Photosynthesis uses carbon dioxide, water, and light to produce glucose and oxygen.
Cellular respiration uses glucose and oxygen to produce carbon dioxide, water, and ATP energy.
The products of one process are the reactants of the other, linking them together.
500
Explain how photosynthesis and cellular respiration work together to move carbon through an ecosystem.
Photosynthesis removes CO₂ from the atmosphere and turns it into glucose (carbon stored in plants).
Cellular respiration breaks down glucose and releases CO₂ back into the atmosphere.
Together, they cycle carbon continuously between organisms and the environment.
500
A claim online shows dramatic results but includes no data, no controlled experiment, and no way for others to test it. Why is this NOT considered real science?
Because it lacks evidence, is not testable, and cannot be repeated — which makes it pseudoscience.
500
A metal block is cut into three smaller pieces. The mass and volume of each piece are different from the original, but this physical property of the metal stays exactly the same.
What is its density?