Answer:
B < Na < Al < K
Explanations:
The size of elements in the periodic table increases from right to left and top to bottom down the group.
For the given question, we will arrange the elements based on atomic size.
For the given elements
• Aluminum has an atomic number of 13
,
• Boron has an atomic number of 5
,
• Potassium has an atomic number of 19
,
• Sodium has an atomic number of 11.
The increasing size will be based on their increasing atomic number and position in the periodic table.
The required increasing size will be B < Na < Al < K