Free Printable Periodic Table Worksheets - Free Printable

Let's go through each question on the "Periodic Table Basics" worksheet and provide clear, accurate answers with explanations.

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1) Which elements in the periodic table have one valence electron?

Answer:
Hydrogen (H), Lithium (Li), Sodium (Na), Potassium (K), Rubidium (Rb), Cesium (Cs), Francium (Fr)

Explanation:
Elements with one valence electron are found in Group 1 of the periodic table (also called the alkali metals, except hydrogen). These elements have their outermost electron in the s-orbital (ns¹ configuration). Hydrogen is an exception because it’s not a metal but has one valence electron.

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2) What do you notice about the number of valence electrons as you move from left to right across a row in the periodic table?

Answer:
The number of valence electrons increases by one as you move from left to right across a period.

Explanation:
Each group in the periodic table corresponds to a specific number of valence electrons. For example:
- Group 1: 1 valence electron
- Group 2: 2 valence electrons
- ...
- Group 18: 8 valence electrons (except helium, which has 2)

So, moving left to right across a period, the number of valence electrons increases sequentially.

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3) What do you notice about the number of energy levels or shells as you move down a group or column in the periodic table?

Answer:
The number of energy levels (shells) increases as you move down a group.

Explanation:
As you go down a group, each successive element has an additional electron shell (principal energy level). For example:
- Lithium (Li) is in Period 2 → 2 energy levels
- Sodium (Na) is in Period 3 → 3 energy levels
- Potassium (K) is in Period 4 → 4 energy levels

So, each period represents a new energy level, and moving down a group adds more shells.

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4) Chemical ________ have similar properties.

Answer:
Chemical elements in the same group have similar properties.

Explanation:
Elements in the same group (column) have the same number of valence electrons, leading to similar chemical behavior. For example, all alkali metals (Group 1) are highly reactive and form +1 ions.

*(Note: The blank may be intended for “groups” or “families,” but the most accurate completion is “elements in the same group.”)*

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5) Noble gases are also called ________ gases because they don’t react with other elements.

Answer:
Noble gases are also called inert gases because they don’t react with other elements.

Explanation:
Noble gases (Group 18) have a full valence shell (8 electrons, except He with 2), making them very stable and unreactive under normal conditions.

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6) In which family would each of these elements be classified?

- Radium – Alkaline earth metals
*(Group 2 – elements like Be, Mg, Ca, etc.)*

- Tin – Metalloids / Post-transition metals
*(Actually, tin is a post-transition metal, but sometimes grouped with metalloids due to its properties. More accurately, it's in Group 14, but not a metalloid. Tin is a metal. So best answer: Post-transition metals or Carbon group.)*
✔ Correct classification: Carbon group (Group 14)

- Iodine – Halogens
*(Group 17 – F, Cl, Br, I, At)*

- Cesium – Alkali metals
*(Group 1 – Li, Na, K, Rb, Cs, Fr)*

Answers:
- Radium – Alkaline earth metals
- Tin – Carbon group (or Post-transition metals)
- Iodine – Halogens
- Cesium – Alkali metals

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7) Write down the number of valence electrons for each of these elements.

- Barium (Ba) = 2
*(Group 2 → 2 valence electrons)*

- Lead (Pb) = 4
*(Group 14 → 4 valence electrons)*

- Bismuth (Bi) = 5
*(Group 15 → 5 valence electrons)*

- Potassium (K) = 1
*(Group 1 → 1 valence electron)*

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8) What do you notice about the melting points as you move from left to right across a period in the periodic table?

Answer:
Melting points generally increase from left to right across a period, then decrease at the end (especially for nonmetals).

Explanation:
- Metals on the left (e.g., Na, Mg, Al) have increasing metallic bonding strength → higher melting points.
- Melting point peaks around transition metals (like iron, chromium).
- Then, for nonmetals (e.g., sulfur, phosphorus, chlorine), melting points drop significantly because they form molecules with weak intermolecular forces.

Example (Period 3):
- Sodium (Na): ~98°C
- Magnesium (Mg): ~650°C
- Aluminum (Al): ~660°C
- Silicon (Si): ~1414°C
- Phosphorus (P): ~44°C
- Sulfur (S): ~119°C
- Chlorine (Cl): −101°C

So, melting point increases up to a peak (around metals), then decreases toward the end of the period.

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Final Answers Summary:

1) H, Li, Na, K, Rb, Cs, Fr
2) Valence electrons increase by one per group
3) Number of energy levels increases
4) elements in the same group
5) inert
6)
- Radium – Alkaline earth metals
- Tin – Carbon group
- Iodine – Halogens
- Cesium – Alkali metals
7)
- Barium = 2
- Lead = 4
- Bismuth = 5
- Potassium = 1
8) Melting points generally increase to a peak, then decrease across a period.

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✔ This completes the worksheet with correct and educational explanations. Let me know if you'd like this formatted as a printable PDF or need a version with blanks filled in!