Answer:
O by increasing atomic number
Step-by-step explanation:
Elements are arranged on the periodic table by increasing atomic number.
The atomic number of an element is the number of protons in such an atom. These protons are the positively charged particles in the atom.
Every atom of an element has a unique number of protons that distinguish it from other atoms.
Based on the number of protons which is the atomic number, elements are arranged on the periodic table.