Place the following elements in increasing order of atomic number: oxygen, calcium, helium.
The elements in increasing order of atomic number are: Helium (atomic number 2), Oxygen (atomic number 8), and Calcium (atomic number 20).
Complete the following task based on the instruction and optional input provided.### Instruction:
Place the following elements in increasing order of atomic number: oxygen, calcium, helium.

### Output:
The elements in increasing order of atomic number are: Helium (atomic number 2), Oxygen (atomic number 8), and Calcium (atomic number 20).