Periodic Table of Elements Worksheets - 15 Worksheets Library - Free Printable
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Step-by-step solution for: Periodic Table of Elements Worksheets - 15 Worksheets Library
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Step-by-step solution for: Periodic Table of Elements Worksheets - 15 Worksheets Library
Let's solve each question based on the periodic table and basic chemistry knowledge. I'll go through them one by one and explain the answers.
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1. Which element has the symbol "Au" and atomic number 79?
- Answer: Gold
- Explanation: The chemical symbol "Au" comes from the Latin word *Aurum*, meaning gold. It is located in group 11, period 6 of the periodic table and has an atomic number of 79.
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2. How many elements are in the second period of the periodic table?
- Answer: 8
- Explanation: The second period (row) includes elements from lithium (Li, atomic number 3) to neon (Ne, atomic number 10). Counting them: Li, Be, B, C, N, O, F, Ne → 8 elements.
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3. What is the atomic number of oxygen (O)?
- Answer: 8
- Explanation: Oxygen is located in period 2, group 16. Its atomic number is 8, meaning it has 8 protons in its nucleus.
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4. How many valence electrons does chlorine (Cl) have?
- Answer: 7
- Explanation: Chlorine is in group 17 (also called the halogens). Elements in group 17 have 7 valence electrons.
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5. Which element has the highest atomic mass in the periodic table?
- Answer: Oganesson (Og)
- Explanation: As of now, the heaviest known element is oganesson (Og), with atomic number 118. It has an atomic mass of approximately 294 u (unified atomic mass units). Note: This is a synthetic element and highly unstable.
> ⚠️ Note: Some versions may list Livermorium (Lv) or others depending on isotopes, but Oganesson is currently the heaviest.
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6. What is the electron configuration of magnesium (Mg)?
- Answer: 1s² 2s² 2p⁶ 3s²
- Explanation: Magnesium has an atomic number of 12, so it has 12 electrons. Filling orbitals in order:
- 1s² (2 electrons)
- 2s² 2p⁶ (8 electrons total so far)
- 3s² (final 2 electrons)
→ Total: 12 electrons
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7. Calculate the number of neutrons in an atom of carbon-14 (¹⁴C).
- Answer: 8
- Explanation:
- Carbon-14 means the isotope has a mass number of 14.
- Atomic number of carbon = 6 → 6 protons
- Number of neutrons = Mass number − Protons = 14 − 6 = 8
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8. Which element has the lowest electronegativity value?
- Answer: Francium (Fr)
- Explanation: Electronegativity increases across a period and decreases down a group. The least electronegative element is typically Francium (Fr), which is at the bottom of group 1 (alkali metals). It has very low electronegativity because it readily loses its outermost electron.
> 🔬 Note: Francium is rare and radioactive, but theoretically has the lowest electronegativity.
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9. What is the symbol and atomic number of the element with 17 protons?
- Answer: Cl, 17
- Explanation: Number of protons = atomic number. So, element with 17 protons has atomic number 17 → Chlorine (Cl).
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10. How many groups are there in the "f-block" of the periodic table?
- Answer: 2
- Explanation: The f-block consists of two series:
- Lanthanides (elements 57–71)
- Actinides (elements 89–103)
These are placed below the main table and represent two rows (or two periods) in the f-block. Each row contains 14 elements, but they are grouped into 2 separate blocks — hence, 2 groups in the f-block.
> ✔ Clarification: While there are 14 elements in each f-series, the f-block itself is considered to have 2 groups: lanthanides and actinides.
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1. Gold
2. 8
3. 8
4. 7
5. Oganesson (Og)
6. 1s² 2s² 2p⁶ 3s²
7. 8
8. Francium (Fr)
9. Cl, 17
10. 2
Let me know if you'd like this formatted for printing or as a filled-out worksheet!
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1. Which element has the symbol "Au" and atomic number 79?
- Answer: Gold
- Explanation: The chemical symbol "Au" comes from the Latin word *Aurum*, meaning gold. It is located in group 11, period 6 of the periodic table and has an atomic number of 79.
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2. How many elements are in the second period of the periodic table?
- Answer: 8
- Explanation: The second period (row) includes elements from lithium (Li, atomic number 3) to neon (Ne, atomic number 10). Counting them: Li, Be, B, C, N, O, F, Ne → 8 elements.
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3. What is the atomic number of oxygen (O)?
- Answer: 8
- Explanation: Oxygen is located in period 2, group 16. Its atomic number is 8, meaning it has 8 protons in its nucleus.
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4. How many valence electrons does chlorine (Cl) have?
- Answer: 7
- Explanation: Chlorine is in group 17 (also called the halogens). Elements in group 17 have 7 valence electrons.
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5. Which element has the highest atomic mass in the periodic table?
- Answer: Oganesson (Og)
- Explanation: As of now, the heaviest known element is oganesson (Og), with atomic number 118. It has an atomic mass of approximately 294 u (unified atomic mass units). Note: This is a synthetic element and highly unstable.
> ⚠️ Note: Some versions may list Livermorium (Lv) or others depending on isotopes, but Oganesson is currently the heaviest.
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6. What is the electron configuration of magnesium (Mg)?
- Answer: 1s² 2s² 2p⁶ 3s²
- Explanation: Magnesium has an atomic number of 12, so it has 12 electrons. Filling orbitals in order:
- 1s² (2 electrons)
- 2s² 2p⁶ (8 electrons total so far)
- 3s² (final 2 electrons)
→ Total: 12 electrons
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7. Calculate the number of neutrons in an atom of carbon-14 (¹⁴C).
- Answer: 8
- Explanation:
- Carbon-14 means the isotope has a mass number of 14.
- Atomic number of carbon = 6 → 6 protons
- Number of neutrons = Mass number − Protons = 14 − 6 = 8
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8. Which element has the lowest electronegativity value?
- Answer: Francium (Fr)
- Explanation: Electronegativity increases across a period and decreases down a group. The least electronegative element is typically Francium (Fr), which is at the bottom of group 1 (alkali metals). It has very low electronegativity because it readily loses its outermost electron.
> 🔬 Note: Francium is rare and radioactive, but theoretically has the lowest electronegativity.
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9. What is the symbol and atomic number of the element with 17 protons?
- Answer: Cl, 17
- Explanation: Number of protons = atomic number. So, element with 17 protons has atomic number 17 → Chlorine (Cl).
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10. How many groups are there in the "f-block" of the periodic table?
- Answer: 2
- Explanation: The f-block consists of two series:
- Lanthanides (elements 57–71)
- Actinides (elements 89–103)
These are placed below the main table and represent two rows (or two periods) in the f-block. Each row contains 14 elements, but they are grouped into 2 separate blocks — hence, 2 groups in the f-block.
> ✔ Clarification: While there are 14 elements in each f-series, the f-block itself is considered to have 2 groups: lanthanides and actinides.
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Final Answers Summary:
1. Gold
2. 8
3. 8
4. 7
5. Oganesson (Og)
6. 1s² 2s² 2p⁶ 3s²
7. 8
8. Francium (Fr)
9. Cl, 17
10. 2
Let me know if you'd like this formatted for printing or as a filled-out worksheet!
Parent Tip: Review the logic above to help your child master the concept of periodic properties worksheet.
