Final answer:
The elements are ordered from largest to smallest atomic radius based on their group and period in the periodic table, with Barium being the largest and Oxygen being the smallest.
Step-by-step explanation:
The student asked to place the elements Calcium, Bromine, Lithium, Aluminum, Phosphorous, Oxygen, Barium, Tin, and Silver in order of atomic radius from largest to smallest. The atomic radius of an element is generally determined by its position in the periodic table. As we move down a group, atomic radius increases because electrons are added to new energy levels, which are further from the nucleus. As we move from left to right across a period, atomic radius decreases due to the increase in the number of protons creating a greater effective nuclear charge, which pulls electrons closer to the nucleus.
The order from largest to smallest atomic radius is:
- Barium (Ba)
- Calcium (Ca)
- Tin (Sn)
- Silver (Ag)
- Aluminum (Al)
- Phosphorous (P)
- Lithium (Li)
- Bromine (Br)
- Oxygen (O)
This order reflects the aforementioned trends with Barium being in Group 2 and having the largest radius due to being the furthest down the group, and Oxygen being smallest since it is to the right and up on the periodic table compared to the others listed.