X is the maximum number of atoms that are in one plane in isobutylene. What is X?

Explanation

To find the maximum number of atoms that are in one plane in isobutylene, we will follow these steps:

### Step 1: Draw the Structure of Isobutylene
Isobutylene (also known as 2-methylpropene) has the following structure:

```
H H
\ /
C
/ \
H C = C
/ \
H H
```

### Step 2: Identify Hybridization of Carbon Atoms
In isobutylene, we have:
- The two carbon atoms involved in the double bond (C=C) are **sp² hybridized**.
- The other two carbon atoms are **sp³ hybridized**.

### Step 3: Analyze the Geometry of sp² Hybridized Carbons
- The sp² hybridized carbons form a **trigonal planar** geometry. This means that all three atoms connected to each sp² carbon (the carbon itself and the two hydrogens) lie in the same plane.
- For the two sp² carbons, we can count:
- 1 carbon from the first sp² carbon
- 2 hydrogens from the first sp² carbon
- 1 carbon from the second sp² carbon
- 2 hydrogens from the second sp² carbon

This gives us a total of **6 atoms** in the same plane from the sp² hybridized carbons.

### Step 4: Analyze the Geometry of sp³ Hybridized Carbons
- The sp³ hybridized carbons have a **tetrahedral** geometry. In a tetrahedral arrangement, only 3 of the 4 substituents can be in the same plane at one time.
- For each sp³ carbon:
- 1 carbon atom is in the same plane with 1 hydrogen atom and 1 hydrogen atom (the other two hydrogens are in a different plane).

So, for the two sp³ hybridized carbons, we can count:
- 1 carbon from the first sp³ carbon
- 1 hydrogen from the first sp³ carbon
- 1 carbon from the second sp³ carbon
- 1 hydrogen from the second sp³ carbon

This gives us an additional **2 atoms** in the same plane from the sp³ hybridized carbons.

### Step 5: Total Count of Atoms in One Plane
Now, we can sum the atoms in the same plane:
- From sp² hybridized carbons: **6 atoms**
- From sp³ hybridized carbons: **2 atoms**

Total = 6 + 2 = **8 atoms**

### Conclusion
Thus, the maximum number of atoms that are in one plane in isobutylene (denoted as X) is **8**.