🧪 Chemistry Test — Final Study Guide Test: Friday, September 4, 2026

🧪 Chemistry Test — Final Study Guide

Test: Friday, September 4, 2026

Part 1 — Classifying Matter

1. What is Matter?

Matter is anything that has mass and takes up space.

Matter can be divided into two major categories:

• Pure Substances

• Mixtures

Pure substances have two types:

• Elements

• Compounds

Mixtures have two types:

• Homogeneous mixtures

• Heterogeneous mixtures

The big picture:

Matter
→ Pure Substance
→ Element or Compound

OR

Matter
→ Mixture
→ Homogeneous or Heterogeneous

2. What is an Element?

An element is a pure substance made of only one type of atom.

Elements cannot be broken down into simpler substances by ordinary chemical means.

Examples:

• Hydrogen (H)

• Oxygen (O)

• Iron (Fe)

• Gold (Au)

• Carbon (C)

🧠 Remember:

ELEMENT = ONE type of atom

3. What is a Compound?

A compound is a pure substance made of two or more different elements that are chemically bonded together.

Examples:

H₂O = Water

• Hydrogen + Oxygen

• Chemically bonded

CO₂ = Carbon Dioxide

• Carbon + Oxygen

• Chemically bonded

NaCl = Sodium Chloride

• Sodium + Chlorine

• Chemically bonded

🧠 Remember:

COMPOUND = elements chemically CONNECTED

4. What is a Mixture?

A mixture contains two or more substances that are physically combined, not chemically bonded.

The substances keep their own properties.

Mixtures can usually be separated using physical methods.

Examples:

• Salad

• Air

• Lemonade

• Bronze

• Trail mix

Important!

A mixture does not have to contain only elements. It can contain elements, compounds, or both.

🧠 Remember:

MIXTURE = substances physically MIXED

5. Element, Compound, or Mixture?

You should be able to identify these:

🚨 Important corrections

Bronze is NOT an element.

Bronze is an alloy, which is a mixture of metals, primarily copper and tin.

Air is NOT a compound.

Air is a mixture of gases, including nitrogen and oxygen.

6. What is a Heterogeneous Mixture?

A heterogeneous mixture is a mixture that is not evenly mixed throughout.

You can often see or identify different parts of the mixture.

Examples:

• Pizza

• Salad

• Oil and water

• Trail mix

🧠 Remember:

Heterogeneous = NOT the same throughout

7. What is a Homogeneous Mixture?

A homogeneous mixture is a mixture that is evenly mixed throughout.

It looks like one substance even though it contains multiple substances.

A homogeneous mixture is also called a solution.

Examples:

• Salt water

• Lemonade

• Soy sauce

• Sugar water

🧠 Remember:

Homogeneous = SAME throughout

8. Homogeneous vs. Heterogeneous

9. What is a Solution?

A solution is a homogeneous mixture.

A solution contains:

Solvent + Solute = Solution

Solvent

The solvent is the substance that does the dissolving.

Solute

The solute is the substance that gets dissolved.

Example: Lemonade

• Water = solvent

• Sugar = solute

• Lemon substances = solute

• Lemonade = solution

🧠 Easy memory trick:

SOLVENT = does the dissolving

SOLUTE = gets dissolved

Part 2 — Atoms

10. What is an Atom?

An atom is the smallest unit of an element that still has the properties of that element.

Everything around you is made of atoms.

11. What are the Two Regions of an Atom?

An atom has two main regions:

1. Nucleus

2. Electron Cloud

Nucleus

The nucleus is the small, dense center of the atom.

It contains:

• Protons

• Neutrons

The nucleus contains almost all of the atom's mass.

Electron Cloud

The electron cloud surrounds the nucleus.

It contains:

• Electrons

The electron cloud makes up most of the atom's volume/space.

🧠 Remember:

Nucleus = MASS

Electron cloud = SPACE

12. The Three Subatomic Particles

🧠 Memory tricks:

P = Positive

N = Neutral

E = Negative

And:

Protons + Neutrons → Nucleus

Electrons → Electron Cloud

13. Atomic Number

The atomic number tells you the number of protons in an atom.

Example:

Carbon has an atomic number of 6.

Therefore:

6 protons

For a neutral atom, the number of electrons is also equal to the number of protons.

So carbon has:

• 6 protons

• 6 electrons

⭐ Important:

Atomic Number = Protons

Neutral atom: Protons = Electrons

14. Atomic Mass

For the problems on your test, use:

Atomic Mass = Protons + Neutrons

To find neutrons:

Neutrons = Atomic Mass − Protons

Example:

An atom has:

• Atomic mass = 23

• Protons = 11

Then:

23 − 11 = 12 neutrons

15. How to Find Protons, Neutrons & Electrons

Use these three rules:

Protons:

Atomic Number = Protons

Electrons:

For a neutral atom:

Electrons = Protons

Neutrons:

Neutrons = Atomic Mass − Protons

16. Practice Atoms

Neon (Ne)

Atomic number = 10

• Protons = 10

• Neutrons = 10

• Electrons = 10

Aluminum (Al)

• Protons = 13

• Neutrons = 14

• Electrons = 13

Sodium (Na)

• Protons = 11

• Neutrons = 12

• Electrons = 11

Boron (B)

• Protons = 5

• Neutrons = 6

• Electrons = 5

17. Periodic Table Practice

🚨 Important correction:

Ca = Calcium

Cd = Cadmium

Do not mix these up!

Part 3 — The Periodic Table

18. Periods

The horizontal rows on the periodic table are called periods.

➡ Periods = Rows

There are 7 periods.

19. Groups/Families

The vertical columns are called groups or families.

⬇ Groups = Columns

Elements in the same group generally have similar chemical properties.

For the main-group elements, they have the same number of valence electrons.

🧠 Remember:

GROUP = GOES DOWN

PERIOD = ACROSS

20. Valence Electrons

Valence electrons are the electrons in the atom's outermost energy level.

They are important because they help determine how an element reacts with other elements.

Elements in the same family generally have the same number of valence electrons, which is why they often behave similarly.

Part 4 — Metals, Nonmetals & Metalloids

21. Metals

Metals are mostly found on the left side of the periodic table.

Metals are generally:

• Shiny

• Solid at room temperature

• Malleable

• Ductile

• Good conductors of heat and electricity

Malleable means:

Can be hammered or pressed into shapes.

Ductile means:

Can be pulled into wires.

22. Nonmetals

Nonmetals are mostly found on the right side of the periodic table.

Nonmetals are generally:

• Poor conductors

• Dull

• Brittle when solid

• Many are gases at room temperature

23. Metalloids

Metalloids are found along the stair-step on the periodic table.

They have properties of both metals and nonmetals.

Many metalloids are semiconductors, meaning they conduct electricity better than nonmetals but not as well as metals.

🧠 Remember:

Metal = Left

Metalloid = Stair-step

Nonmetal = Right

24. Group & Period Practice

Group 2, Period 2

The element is:

Beryllium (Be)

Type:

Metal

✅ Correct.

Group 14, Period 3

The element is:

Silicon (Si)

Type:

Metalloid

🚨 Important correction: Your original notes said nonmetal, but silicon is a metalloid.

Group 18, Period 4

The element is:

Krypton (Kr)

Type:

Nonmetal

✅ Correct.

Part 5 — Reactivity

25. What is Reactivity?

Reactivity describes how easily an element reacts with other substances.

Different families have different levels of reactivity.

26. Group 1 — Alkali Metals

Group 1 elements are very reactive metals.

Examples:

• Lithium

• Sodium

• Potassium

Sodium (Na)

Sodium is highly reactive.

27. Group 17 — Halogens

Group 17 elements are very reactive nonmetals.

Examples:

• Fluorine

• Chlorine

• Bromine

• Iodine

28. Group 18 — Noble Gases

Group 18 contains the noble gases.

Examples:

• Helium

• Neon

• Argon

• Krypton

They are generally very unreactive.

This is because their outer energy level is full.

29. Sodium vs. Iron

Which is more reactive?

Sodium (Na) ✅

Sodium is a Group 1 alkali metal and is highly reactive.

30. Which Elements Have Similar Properties to Helium?

Helium is in Group 18.

Other elements in the same family include:

• Neon (Ne)

• Argon (Ar)

• Krypton (Kr)

So if asked for two:

Neon and Argon

31. Which Families Are Highly Reactive?

The two important highly reactive families to know are:

Group 1 — Alkali Metals

Very reactive metals.

Group 17 — Halogens

Very reactive nonmetals.

These groups commonly react with each other.

Example:

Sodium + Chlorine → Sodium Chloride

Na + Cl → NaCl

This creates the compound table salt.

⭐ SUPER IMPORTANT: Memorize These!

If you don't have much time, focus on these facts:

Matter

• Element = one type of atom

• Compound = elements chemically bonded

• Mixture = substances physically combined

• Homogeneous = evenly mixed

• Heterogeneous = unevenly mixed

• Solution = homogeneous mixture

• Solvent = does the dissolving

• Solute = gets dissolved

Atoms

• Proton = positive

• Neutron = neutral

• Electron = negative

• Protons + neutrons = nucleus

• Electrons = electron cloud

• Nucleus = most of the mass

• Electron cloud = most of the space

• Atomic number = protons

• Neutral atom: protons = electrons

• Neutrons = atomic mass − protons

• Atomic mass = protons + neutrons

Periodic Table

• Periods = horizontal rows

• Groups = vertical columns

• Same group = similar properties

• Valence electrons = outermost electrons

• Metals = left

• Nonmetals = right

• Metalloids = stair-step

• Group 1 = very reactive metals

• Group 17 = very reactive nonmetals

• Group 18 = noble gases / very unreactive

🧠 Quick Memory Sheet

Try memorizing these phrases:

Element = ONE

Compound = CHEMICALLY BONDED

Mixture = PHYSICALLY MIXED

Homogeneous = SAME

Heterogeneous = DIFFERENT

Solvent = DISSOLVES

Solute = DISSOLVED

Atomic Number = PROTONS

Mass = PROTONS + NEUTRONS

Periods = ROWS

Groups = COLUMNS

Metal = LEFT

Metalloid = STAIR-STEP

Nonmetal = RIGHT

Group 1 = REACTIVE METALS

Group 17 = REACTIVE NONMETALS

Group 18 = NOBLE GASES

📝 Final Practice Questions

Before your test, cover the answers and see if you can answer these from memory:

1. What are the two major categories of matter?

2. What is an element?

3. What is a compound?

4. What is a mixture?

5. Is H₂O an element, compound, or mixture?

6. Is air an element, compound, or mixture?

7. Is bronze an element, compound, or mixture?

8. What is the difference between homogeneous and heterogeneous?

9. What is another name for a homogeneous mixture?

10. What is a solute?

11. What is a solvent?

12. What is the solvent in lemonade?

13. What are the two regions of an atom?

14. Where are protons located?

15. Where are neutrons located?

16. Where are electrons located?

17. What charge does a proton have?

18. What charge does a neutron have?

19. What charge does an electron have?

20. What does the atomic number tell you?

21. How do you calculate neutrons?

22. How do you calculate electrons in a neutral atom?

23. What are horizontal rows called?

24. What are vertical columns called?

25. What are valence electrons?

26. Where are metals located?

27. Where are nonmetals located?

28. Where are metalloids located?

29. What type of element is silicon?

30. What element is Group 2, Period 2?

31. What element is Group 18, Period 4?

32. Which is more reactive: sodium or iron?

33. Which group contains highly reactive metals?

34. Which group contains highly reactive nonmetals?

35. What family does helium belong to?

36. Name two elements similar to helium.

🎯 One Last Thing

The most important corrections from your original notes are:

• Bronze = Mixture

• Air = Mixture

• Silicon = Metalloid

• Ca = Calcium, while Cd = Cadmium

• Heterogeneous = not evenly mixed, not simply "easy to separate"

• Homogeneous = evenly mixed, not "cannot be separated"

• Mixtures contain two or more substances, not necessarily just elements

• Atomic number = number of protons

• Group 1 + Group 17 is the important reactive metal/nonmetal combination to remember