Final answer:
To arrange atoms in order of decreasing atomic radii, consider the periodic trends that indicate atomic size decreases across a period and increases down a group. The correct order for Sr, Ca, Si, Cl, when listed from largest to smallest atomic radius, is Cs, Bi, Sr, Ge, Al.
Step-by-step explanation:
When arranging atoms in order of decreasing atomic radii, it's important to recognize the trends on the periodic table. Atomic radii decrease from left to right across a row due to increasing nuclear charge, which pulls electrons closer to the nucleus, and they increase from top to bottom down a column as additional electron shells are added, which makes the atomic radius larger. Let's apply this knowledge to list the atoms in the order requested.
Decreasing Atomic Radii Order
The elements given are Sr, Ca, Si, Cl. Based on their positions in the periodic table, we can order them as follows:
Cs - Located at the bottom of Group 1, which means it has the largest radius among the given atoms.
Bi - Below aluminum in Group 15, relatively large radius due to additional electron shells.
Sr - Below calcium in Group 2, with a radius smaller than bismuth but larger than the remaining atoms.
Ge - To the right of aluminum in the same period, with fewer electron shells than strontium or bismuth and a smaller radius due to increased effective nuclear charge.
Al - To the left of germanium and with fewer electron shells, which leads to an even smaller radius.
This ordering follows the general trends of atomic size on the periodic table and shows how atomic radius changes across different elements.