Middle School Science Quiz: How Atoms Shape Substances

What this quiz covers

This quiz focuses on How Atoms Shape Substances, giving you a quick way to practice the rules, question types, and explanations that matter most for Middle School Science.

How to use this quiz

Try each quiz question before looking at the correct answer. Use the explanations to review missed ideas, then come back to similar questions until the pattern feels familiar.

Question 1

1. Diamond and graphite have different properties because diamond has carbon atoms but graphite has iron atoms mixed in.
2. Diamond is hard because its carbon atoms are connected in a strong 3D network, while graphite is soft because its carbon atoms are in layers that can slide past each other. (correct answer)
3. Graphite is soft because it is a liquid at room temperature, but diamond is solid at room temperature.
4. Diamond is hard because it is used in jewelry, while graphite is soft because it is used in pencils.

Question 2

1. Carbon atoms bonded in flat layers that can slide past each other easily. (correct answer)
2. Carbon atoms bonded in a strong 3D network where every atom is tightly connected in all directions.
3. Carbon atoms spread far apart with no connections, like a gas at room temperature.
4. Carbon atoms mixed with sodium and chlorine atoms in a repeating crystal pattern.

Question 3

1. The different ratio/number of atoms in each molecule ($\mathrm{H_2O}$ vs $\mathrm{H_2O_2}$) makes them different substances with different properties. (correct answer)
2. They are the same substance because they use the same elements, so they must behave the same way.
3. Hydrogen peroxide bleaches because it is always a solid at room temperature.
4. Water cannot disinfect because it has no molecules, only single atoms.

Question 4

1. O$_2$ and O$_3$ must have the same properties because they are both oxygen.
2. O$_3$ is more reactive because it has a different number of oxygen atoms in each molecule, which changes the molecule's structure and behavior. (correct answer)
3. O$_3$ is more reactive because it contains carbon atoms.
4. O$_2$ is less reactive because it is always found as a liquid at room temperature.

Question 5

1. Iron conducts because metal atoms are arranged in a regular array that allows electricity to pass through easily, while plastics are made of molecules that do not allow electricity to move as easily. (correct answer)
2. Plastics do not conduct because they are always colder than iron.
3. Iron conducts because it is gray, while plastics do not conduct because they can be many colors.
4. Plastics do not conduct because they contain only metal atoms, unlike iron.

Question 6

1. Graphite is soft because it contains different atoms than diamond, such as iron (Fe).
2. Diamond is hard because its carbon atoms are bonded in a strong 3D network, while graphite is soft because its carbon atoms are arranged in layers that slide past each other. (correct answer)
3. Diamond is hard because it is colder than graphite at room temperature.
4. Diamond and graphite should have the same properties because they are both carbon.

Question 7

1. Because both contain oxygen, they must be in the same state at room temperature.
2. Water and carbon dioxide have different kinds and numbers of atoms, leading to different particle structures and different attractions between particles, so they can be liquid vs. gas at room temperature. (correct answer)
3. Carbon dioxide is a gas because its atoms are heavier than water's atoms.
4. Water is liquid because liquids do not contain atoms, but carbon dioxide is gas because gases do contain atoms.

Question 8

1. They have different properties because $\mathrm{H_2O_2}$ has a different ratio/number of oxygen atoms than $\mathrm{H_2O}$, so the molecules are not the same and behave differently. (correct answer)
2. They have different properties because $\mathrm{H_2O}$ contains carbon atoms but $\mathrm{H_2O_2}$ does not.
3. They have different properties because any substance with oxygen atoms must be a bleach.
4. They have different properties because the word "peroxide" makes a substance reactive, not the atoms.

Question 9

1. They are made of different kinds and numbers of atoms, so the particles and structures are different and cause different properties. (correct answer)
2. They have different properties only because salt crystals are always bigger than sugar crystals.
3. They have different properties because sugar is a mixture of salt and water.
4. They have different properties because taste is not connected to atoms at all.

Question 10

1. Because $\mathrm{H_2O}$ has hydrogen and oxygen arranged as water molecules, it has attractions that let it stay liquid at room temperature, while $\mathrm{CO_2}$ molecules move more freely and stay a gas. (correct answer)
2. All substances with oxygen atoms must be liquids, so $\mathrm{CO_2}$ should be liquid too.
3. Water is liquid only because it is clear, and carbon dioxide is gas only because it is invisible.
4. The state of matter is decided by the container shape, not by atoms.

Question 11

1. The substances have different kinds of atoms and different structures: $\mathrm{CO_2}$ is made of separate molecules, while NaCl forms a repeating crystal structure, leading to very different properties. (correct answer)
2. Anything with carbon must be a gas at room temperature.
3. NaCl is solid only because it is white, and $\mathrm{CO_2}$ is gas only because it is invisible.
4. State of matter is not related to atoms; it depends only on whether the sample is in a small or large container.

Question 12

1. Salt holds its shape because its particles are locked into a repeating crystal structure, while water flows because it is made of separate molecules that can move past one another. (correct answer)
2. Water flows because it has a taste, and salt is solid because it has no taste.
3. Salt is solid because it contains water trapped inside it, and water is liquid because it contains salt.
4. Water and salt behave differently only because salt is older than water.

Question 13

1. Sample X will likely be harder because layers sliding increases strength.
2. Sample Y will likely be softer because a 3D network makes it easier to bend.
3. Sample X will likely be softer/slipperier, and Sample Y will likely be harder, because sliding layers weaken the solid while a 3D network holds it rigidly. (correct answer)
4. Both must have the same hardness because they are both solids.

Question 14

1. The continuous 3D network solid is more likely to be very hard and not dissolve easily, while the separate-molecule solid is more likely to dissolve more easily. (correct answer)
2. The separate-molecule solid is more likely to be the hardest solid because molecules are stronger than networks.
3. Both solids must have the same hardness because they are both solids.
4. The continuous 3D network solid is more likely to flow like a liquid at room temperature.

Question 15

1. They have different properties because $\mathrm{O_2}$ is an element and $\mathrm{O_3}$ is not made of oxygen.
2. They have different properties because having a different number of atoms in each molecule changes the molecule's structure and how it interacts with other substances. (correct answer)
3. They have different properties because $\mathrm{O_3}$ is always a liquid and $\mathrm{O_2}$ is always a solid at room temperature.
4. They have different properties because reactivity determines how many atoms are in a molecule, not the other way around.

Question 16

1. Diamond is hard because its carbon atoms are bonded in a strong 3D network throughout the solid, while graphite is soft because its carbon atoms are arranged in layers that can slide past each other. (correct answer)
2. Diamond is hard because it contains iron atoms, while graphite is soft because it contains oxygen atoms.
3. Diamond and graphite must have the same properties because they are both made of carbon atoms.
4. Graphite is soft because it is a liquid at room temperature, while diamond is hard because it is a gas at room temperature.

Question 17

1. Salt and sugar are made of different kinds and numbers of atoms, which leads to different structures and properties like taste and how they dissolve. (correct answer)
2. Salt tastes salty because it is white, and sugar tastes sweet because it is also white.
3. Salt and sugar must have the same atoms because both are crystals.
4. Sugar is sweet because it is a solid at room temperature, while salt is salty because it is a gas at room temperature.

Question 18

1. Because sugar has many more atoms, it can have more complex interactions (like tasting sweet and dissolving), while $\mathrm{O_2}$ is simpler and has fewer kinds of behaviors. (correct answer)
2. The number of atoms never affects properties; only the color of the substance matters.
3. Sugar and $\mathrm{O_2}$ must have the same properties because both contain oxygen atoms.
4. Sugar has more atoms, so it must always be a gas at room temperature.

Question 19

1. They behave differently because $\mathrm{H_2O_2}$ has an extra oxygen atom compared to $\mathrm{H_2O}$, so the ratio and structure of atoms are different, leading to different properties. (correct answer)
2. They behave differently because both have the same atoms, so the difference must come only from their color.
3. They behave differently because water is a liquid, and all liquids are safe to drink.
4. They behave differently because disinfectants are labeled that way, which changes what atoms they contain.

Question 20

1. Iron conducts electricity because its atoms are arranged in a metal structure where electrons can move easily through the solid. (correct answer)
2. Iron conducts electricity because it is gray and shiny, and shiny objects always conduct.
3. Iron conducts electricity because it is heavy, and heavier substances always conduct better.
4. Iron conducts electricity because it is magnetic, and magnetism causes electricity to flow without atoms involved.