What is the shape of 1s and `2s` orbital .Give two point of difference between `1s` and `2s` orbital

Explanation

### Step-by-Step Solution:

1. **Shape of 1s and 2s Orbitals**:
- Both the 1s and 2s orbitals are spherical in shape. This spherical shape is a characteristic of all s orbitals, regardless of the principal quantum number (n). The shape is determined by the azimuthal quantum number (l), which is 0 for s orbitals.

2. **Difference Based on Energy**:
- The energy of an orbital can be determined using the formula \( n + l \), where \( n \) is the principal quantum number and \( l \) is the azimuthal quantum number.
- For the 1s orbital:
- \( n = 1 \)
- \( l = 0 \)
- Therefore, \( n + l = 1 + 0 = 1 \)
- For the 2s orbital:
- \( n = 2 \)
- \( l = 0 \)
- Therefore, \( n + l = 2 + 0 = 2 \)
- Since the value of \( n + l \) is higher for the 2s orbital, it has higher energy compared to the 1s orbital. Thus, the energy of the 1s orbital is less than that of the 2s orbital.

3. **Difference Based on Number of Nodes**:
- The number of nodes in an orbital can be calculated using the formula \( n - 1 \).
- For the 1s orbital:
- \( n = 1 \)
- Therefore, the number of nodes = \( 1 - 1 = 0 \) (indicating there are no nodes in the 1s orbital).
- For the 2s orbital:
- \( n = 2 \)
- Therefore, the number of nodes = \( 2 - 1 = 1 \) (indicating there is one node in the 2s orbital).
- Hence, the 1s orbital has no nodes, while the 2s orbital has one node.

### Summary of Differences:
1. **Energy**: The energy of the 1s orbital is less than that of the 2s orbital.
2. **Number of Nodes**: The 1s orbital has 0 nodes, while the 2s orbital has 1 node.