The increasing order of the atomic radii of the following elements is :
(a) C (b) O(c) F(d) ( e) Br

Options

A. `(C) lt(b) lt (a) lt (d) lt (e) `
B. `(b) lt(c) lt (d) lt (a) lt (e) `
C. `(b) lt(c) lt (b) lt (a) lt (e) `
D. `(a) lt(b) lt (c) lt (d) lt (e) `

Answer

To determine the increasing order of atomic radii for the elements C (Carbon), O (Oxygen), F (Fluorine), and Br (Bromine), we need to consider the periodic trends in atomic size.

### Step-by-Step Solution:

1. **Identify the Position in the Periodic Table:**
- Carbon (C) is in Group 14, Period 2.
- Oxygen (O) is in Group 16, Period 2.
- Fluorine (F) is in Group 17, Period 2.
- Bromine (Br) is in Group 17, Period 4.

2. **Understand Atomic Radius Trends:**
- Atomic radius decreases across a period from left to right due to increasing nuclear charge, which pulls the electrons closer to the nucleus.
- Atomic radius increases down a group due to the addition of electron shells.

3. **Compare the Elements:**
- Carbon (C) is the first element in the list and has the largest atomic radius among C, O, and F since it is to the left of them in the same period.
- Oxygen (O) is next and has a smaller atomic radius than Carbon.
- Fluorine (F) is to the right of both C and O, thus it has the smallest atomic radius among these three.
- Bromine (Br) is in a lower period (Period 4) and will have a larger atomic radius than all three (C, O, F) since it is further down the group.

4. **Establish the Order:**
- From the above comparisons, we find the order of atomic radii from smallest to largest:
- F < O < C < Br

5. **Final Answer:**
- The increasing order of atomic radii is: F < O < C < Br