Let's solve each question step by step based on the periodic table and basic chemistry principles.
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1. What is the element symbol for Californium?
Answer: Cf
- Californium is a synthetic element with atomic number 98.
- Its chemical symbol is
Cf.
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2. How many protons are present in an atom of Bismuth?
Answer: 83
- The number of protons in an atom is equal to its
atomic number.
- Bismuth (Bi) has an atomic number of
83, so it has
83 protons.
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3. To which group element does Argon belong?
Answer: Group 18 (Noble Gases)
- Argon (Ar) is a noble gas.
- It belongs to
Group 18 of the periodic table, also known as the
noble gases.
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4. All families have the same number of ________ electrons.
Answer: valence
- Elements in the same
group (family) have the same number of
valence electrons.
- This is why they exhibit similar chemical properties.
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5. Nobel gases have a ________ valence shell.
Answer: full (or complete)
- Noble gases have a
completely filled valence shell, making them very stable and chemically inert.
- They have
8 valence electrons (except helium, which has 2).
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6. Alkaline-earth metals are the elements in the ____ column.
Answer: 2nd
- Alkaline-earth metals are in
Group 2 of the periodic table.
- This includes elements like Be, Mg, Ca, Sr, Ba, Ra.
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7. Write down the element from the set that matches the given criteria.
We are given four atoms for each criterion, and we need to determine which one best fits the property.
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a) Largest size (atomic radius)
| Atom | Element |
|------|--------|
| 1 | Chlorine |
| 2 | Sodium |
| 3 | Silicon |
| 4 | Aluminum |
-
Trend: Atomic size increases down a group and decreases across a period (left to right).
- Among these:
- Sodium (Na) is in
Group 1, Period 3 → large size
- Magnesium, Aluminum, Silicon, Chlorine are to the right → smaller
- So,
Sodium (Na) has the largest atomic size.
✔ Answer: Sodium
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####
b) Highest electronegativity
| Atom | Element |
|------|--------|
| 1 | Calcium |
| 2 | Beryllium |
| 3 | Radium |
| 4 | Magnesium |
- Electronegativity increases across a period and decreases down a group.
- All these are
metals, so low electronegativity.
- But among them:
-
Beryllium (Be) is farthest to the right (Group 2) and in the top period (Period 2), so it will have the highest electronegativity among these.
- Calcium and Radium are larger and more metallic → lower EN.
- Magnesium is in between.
✔ Answer: Beryllium
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####
c) Ionization energy
| Atom | Element |
|------|--------|
| 1 | Calcium |
| 2 | Bromine |
| 3 | Arsenic |
| 4 | Iron |
- Ionization energy increases across a period and decreases down a group.
-
Bromine (Br) is a nonmetal in Group 17, Period 4 → high IE.
- Calcium (Ca): metal, low IE.
- Arsenic (As): metalloid, moderate IE.
- Iron (Fe): transition metal, moderate IE.
Among these,
Bromine has the
highest ionization energy because it’s on the right side of the periodic table and highly electronegative.
✔ Answer: Bromine
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✔ Final Answers:
1.
Cf
2.
83
3.
Group 18
4.
valence
5.
full (or complete)
6.
2nd
7.
- Largest size:
Sodium
- Highest electronegativity:
Beryllium
- Ionization energy:
Bromine
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Parent Tip: Review the logic above to help your child master the concept of 8th grade periodic table worksheet.
