A few arrangements are given as.
I. `He lt Ne lt Ar`
II. `Li lt C lt O lt F`
III. `Cl lt P lt Mg lt Na`
IV. `Li lt N lt Cl lt F`
Now, read the given passage and fill in the blanks by selecting an appropriate option.
In arrangement I, elements are arranged in increasing order of `ul((i))` II, elements are arranged in increasing order of `ul((ii))` , in III, elements are arranged in increasing order of `ul((iii))` while in arrangement IV, elements are arranged in increasing order of `ul((iv))`.

Options

A. `{:("(i)","(ii)","(iii)","(iv)"),("Atomic radius","Valency","Number of electron shells","Electronegativity"):}`
B. `{:("(i)","(ii)","(iii)","(iv)"),("Atomic size","Metallic character"," Valency","Number of electron shells"):}`
C. `{:("(i)","(ii)","(iii)","(iv)"),("Valency","Number of electron shells"," Electronegativity","Atomic size"):}`
D. `{:("(i)","(ii)","(iii)","(iv)"),("Number of electron shells","Number of valence shells"," Atomic size","Electronegativit"):}`

Answer

To solve the question, we need to analyze each arrangement of elements and determine the property by which they are arranged in increasing order.

### Step-by-Step Solution:

1. **Arrangement I: `He < Ne < Ar`**
- These elements are helium (He), neon (Ne), and argon (Ar). They are all noble gases and belong to Group 18 of the periodic table.
- The correct property for this arrangement is **atomic radius**. As we move down the group, the atomic radius increases due to the addition of electron shells.
- **Fill in the blank (i):** atomic radius

2. **Arrangement II: `Li < C < O < F`**
- The elements are lithium (Li), carbon (C), oxygen (O), and fluorine (F). They are arranged in increasing order across the second period of the periodic table.
- The correct property for this arrangement is **number of valence electrons**. Lithium has 1, carbon has 4, oxygen has 6, and fluorine has 7 valence electrons.
- **Fill in the blank (ii):** number of valence electrons

3. **Arrangement III: `Cl < P < Mg < Na`**
- The elements are chlorine (Cl), phosphorus (P), magnesium (Mg), and sodium (Na). They belong to different groups but are in the same period.
- The correct property for this arrangement is **atomic size**. Sodium (Na) has the largest atomic size because it is in Group 1, while chlorine (Cl) has the smallest size among them.
- **Fill in the blank (iii):** atomic size

4. **Arrangement IV: `Li < N < Cl < F`**
- The elements are lithium (Li), nitrogen (N), chlorine (Cl), and fluorine (F). They are arranged across the second and third periods.
- The correct property for this arrangement is **electronegativity**. Electronegativity increases across a period, so fluorine has the highest electronegativity, followed by chlorine, nitrogen, and then lithium.
- **Fill in the blank (iv):** electronegativity

### Final Answers:
- (i) atomic radius
- (ii) number of valence electrons
- (iii) atomic size
- (iv) electronegativity