The Periodic Table — Chemistry Unit 2 practice.
This unit covers element groups, periodic trends and metals nonmetals metalloids — essential concepts for Chemistry. Use our interactive study games to test your understanding, or review questions in traditional format below.
Pick a mode. Play.
Answer questions as fast as you can. 2 minutes on the clock. Build streaks for bonus points!
Don't want to play?
Review the questions traditionally. Click to expand.
Questions loading...
Focus on understanding.
Focus on understanding core concepts before memorizing details. Use the game modes to test yourself repeatedly — spaced repetition is proven to boost long-term retention.
This unit covers element groups, periodic trends and metals nonmetals metalloids — essential concepts for Chemistry. Use our interactive study games to test your understanding, or review questions in traditional format below.
Key Concepts Breakdown
1 Element Groups
The periodic table is organized into vertical columns called groups (or families), numbered 1–18. Elements in the same group have the same number of valence electrons and therefore similar chemical properties. Students must know the names and key properties of the major groups: alkali metals (Group 1), alkaline earth metals (Group 2), halogens (Group 17), and noble gases (Group 18).
Key Points
- Group 1 (alkali metals): 1 valence electron, highly reactive, react violently with water to form hydroxides and hydrogen gas
- Group 17 (halogens): 7 valence electrons, highly reactive nonmetals, readily gain 1 electron to form -1 ions
- Group 18 (noble gases): 8 valence electrons (except He with 2), chemically inert, full outer shell
- Transition metals (Groups 3–12): variable oxidation states, form colored compounds, good conductors
Which element is most chemically similar to sodium (Na)? A) Magnesium (Mg) B) Potassium (K) C) Chlorine (Cl) D) Argon (Ar)
Sodium is in Group 1 with 1 valence electron. Chemical similarity is determined by the same group, not the same period. Potassium (K) is also in Group 1, so it also has 1 valence electron and behaves similarly. The answer is B.
2 Periodic Trends
Periodic trends describe predictable changes in atomic properties as you move across a period (left to right) or down a group (top to bottom). The four trends students must know for exams are atomic radius, ionization energy, electronegativity, and electron affinity. These trends are all explained by the interplay of nuclear charge and electron shielding.
Key Points
- Atomic radius increases going down a group (more electron shells) and decreases going left to right across a period (higher nuclear charge pulls electrons in)
- Ionization energy increases left to right across a period and decreases going down a group
- Electronegativity increases left to right and decreases going down; fluorine (F) has the highest electronegativity
- Across a period, increasing nuclear charge (more protons) with the same shielding pulls valence electrons closer and tighter
Arrange the following in order of increasing atomic radius: Na, Cl, K. Explain your reasoning.
Cl is in Period 3 to the right of Na, so Cl has a smaller radius than Na (same period, more protons). K is directly below Na in Group 1 and has an extra electron shell, giving it the largest radius. The correct order from smallest to largest is: Cl < Na < K.
3 Metals Nonmetals Metalloids
Elements are classified as metals, nonmetals, or metalloids based on their physical and chemical properties. Metals are found on the left and center of the periodic table; nonmetals on the upper right; metalloids form a staircase boundary between them. Students must be able to identify examples of each and compare their properties.
Key Points
- Metals: shiny (lustrous), malleable, ductile, good conductors of heat and electricity, tend to lose electrons and form positive ions (cations)
- Nonmetals: dull, brittle (if solid), poor conductors (insulators), tend to gain electrons and form negative ions (anions) or share electrons in covalent bonds
- Metalloids (semimetals): B, Si, Ge, As, Sb, Te — have properties of both metals and nonmetals; semiconductors used in electronics
- The staircase line on the periodic table separates metals (left) from nonmetals (right); metalloids sit along this line
Silicon (Si) is used in computer chips. Based on its classification, explain why silicon is chosen over copper (a metal) or sulfur (a nonmetal) for this application.
Silicon is a metalloid and acts as a semiconductor — it can conduct electricity under certain conditions but not others, which is essential for controlling electrical signals in circuits. Copper always conducts (too conductive for switching), and sulfur never conducts (too insulating). Silicon's intermediate, controllable conductivity makes it ideal.
Questions, answered.
What is The Periodic Table?
The Periodic Table is Unit 2 of Chemistry, covering element groups, periodic trends and metals nonmetals metalloids.
How to study for Chemistry Unit 2?
Start with the Quick Summary above, review the Key Concepts, then test yourself with our interactive study games. Aim for 80%+ accuracy before moving on.
How many questions are in this unit?
This unit has 25+ review questions across 5 different game modes.