Free Printable Periodic Trends Worksheets - Free Printable

Let's go through the Periodic Trends Worksheet step by step and solve each question with explanations based on periodic trends.

---

1. Circle the best answer that has the:

#### a) Smallest electron affinity
Elements: N, P, As, Sb, Bi
- Electron affinity generally increases (becomes more negative) across a period and decreases down a group.
- Nitrogen (N) has very low electron affinity because it has a half-filled p-subshell (stable configuration), so adding an electron is unfavorable.
- So, N has the smallest (least negative) electron affinity.

✔ Answer: N

---

#### b) Largest electronegativity
Elements: Ga, Ge, As, Sc
- Electronegativity increases across a period and decreases down a group.
- Among these:
- Ga (Group 13), Ge (14), As (15), Sc (Group 3)
- As is furthest right → highest electronegativity
- Sc is a transition metal and has low electronegativity

✔ Answer: As

---

#### c) Largest ionization energy
Elements: O, S, Sc, Te, Po
- Ionization energy increases across a period and decreases down a group.
- O is in Period 2, Group 16 — high IE.
- But Sc is a transition metal (low IE due to shielding).
- Te and Po are heavier → lower IE.
- O has higher IE than S, but note: O < N due to electron repulsion, but among these, O is still higher than S, Sc, etc.
- However, Sc has very low IE (it's a metal).
- The highest IE among these is O, but wait — S is below O, so O > S.
- Actually, O has higher IE than S, Te, Po.
- But Sc is a metal → very low IE.
- So, O has the largest ionization energy here.

✔ Answer: O

> Note: Oxygen has a slightly lower IE than nitrogen due to electron pairing, but it’s still higher than S, Te, Po, and especially Sc.

---

#### d) Lowest ionization energy
Elements: O, S, Se, Te, Po
- Ionization energy decreases down a group.
- Po (Polonium) is at the bottom → lowest IE.

✔ Answer: Po

---

#### e) Smallest atomic radius
Elements: F, Cl, Br, I, At
- Atomic radius increases down a group.
- F is at the top → smallest radius.

✔ Answer: F

---

#### f) Largest atomic radius
Elements: Li, Na, K, Rb, Cs
- All alkali metals, increasing down the group.
- Cs is at the bottom → largest radius.

✔ Answer: Cs

---

2. Low ionization energy is a characteristic of a ________

- Low IE means atoms lose electrons easily → typical of metals, especially alkali metals.

✔ Answer: Metal

---

3. What does atomic radius measure?

- It measures the distance from the nucleus to the outermost electron shell (or the average distance of valence electrons from the nucleus).

✔ Answer: The size of an atom; the distance from the nucleus to the outermost electrons.

---

4. Describe the change in the atomic size across a period and down a group.

- Across a period (left to right): Atomic radius decreases because effective nuclear charge increases, pulling electrons closer.
- Down a group: Atomic radius increases because new electron shells are added, increasing distance from nucleus.

✔ Answer:
> Across a period: atomic radius decreases.
> Down a group: atomic radius increases.

---

5. Which element has the largest atomic radius?

- This is a general question. Assuming we’re considering common elements, Cesium (Cs) or Francium (Fr) have the largest atomic radii.
- Since Fr is radioactive and rare, Cs is typically considered the largest stable element.

✔ Answer: Cesium (Cs)

---

6. Explain the main difference between metals and nonmetals.

- Metals tend to lose electrons to form cations; they are shiny, malleable, good conductors.
- Nonmetals tend to gain electrons to form anions; they are brittle, poor conductors (except graphite), dull.

✔ Answer: Metals tend to lose electrons and form positive ions, while nonmetals tend to gain electrons and form negative ions.

---

7. Determine if the listed pairs of elements have similar or different properties.

| Pair | Similar or Different? | Reason |
|------|------------------------|--------|
| a) Potassium & Rubidium | ✔ Similar | Both alkali metals (Group 1), same chemical behavior |
| b) Calcium & Barium | ✔ Similar | Both alkaline earth metals (Group 2) |
| c) Sodium & Chlorine | ✘ Different | Na is metal, Cl is nonmetal; opposite behaviors |
| d) Helium & Krypton | ✔ Similar | Both noble gases (Group 18), inert |
| e) Phosphorus & Oxygen | ✘ Different | P is nonmetal, O is nonmetal, but different groups (P: 15, O: 16); different chemistry |
| f) Lithium & Fluorine | ✘ Different | Li is metal (Group 1), F is nonmetal (Group 17); opposite tendencies |

✔ Answers:
a) Similar
b) Similar
c) Different
d) Similar
e) Different
f) Different

---

8. Which element has the largest electronegativity?

- Fluorine (F) is the most electronegative element (value ≈ 3.98 on Pauling scale).

✔ Answer: Fluorine (F)

---

9. Which group (name) would have the lowest ionization energies?

- Alkali metals (Group 1) have the lowest ionization energies because they have one valence electron and large atomic sizes.

✔ Answer: Alkali metals

---

10. Which group (name) has the highest ionization energies?

- Noble gases (Group 18) have the highest ionization energies because they have full valence shells and are very stable.

✔ Answer: Noble gases

---

✔ Final Answers Summary:

1.
a) N
b) As
c) O
d) Po
e) F
f) Cs

2. Metal

3. The distance from the nucleus to the outermost electrons

4.
- Across a period: Decreases
- Down a group: Increases

5. Cesium (Cs)

6. Metals lose electrons to form cations; nonmetals gain electrons to form anions.

7.
a) Similar
b) Similar
c) Different
d) Similar
e) Different
f) Different

8. Fluorine (F)

9. Alkali metals

10. Noble gases

---

Let me know if you'd like this formatted as a printable worksheet!