By the position of the elements in the periodic system, determine which element has a larger radius of the atom: a) boron or oxygen

By the position of the elements in the periodic system, determine which element has a larger radius of the atom: a) boron or oxygen; b) beryllium or calcium; c) fluorine or bromine. Explain the answer

a) Boron; b) calcium; c) bromine.
From top to bottom in the group, the radius of the atom increases, as the number of electron layers increases.
From left to right along the period, the radius of the atom will decrease because more electrons appear on the outer layer and its bond with the nucleus increases.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.