instructions: in each question, list the elements from least to greatest atomic radius:\n4) cesium (cs)…

Explanation:

4)

Step1: Analyze the group trend

In the alkali metal group (Group 1A), as the atomic number increases (from Na to K to Cs), the number of electron shells increases. According to the rule that atomic radius increases down a group, we can compare their atomic radii.

Step2: List the order

Since Na has fewer electron shells than K, and K has fewer electron shells than Cs, the order from least to greatest atomic radius is (Na<K<Cs).

5)

Step1: Analyze the period trend

In the same period (Period 3), as the atomic number increases from Mg to Al to P, the nuclear charge increases. The electrons are added to the same shell. According to the rule that atomic radius decreases across a period (from left - to - right), we can compare their atomic radii.

Step2: List the order

Since Mg is on the leftmost, then Al, and P is on the rightmost in Period 3, the order from least to greatest atomic radius is (P < Al<Mg).

6)

Step1: Compare across periods and groups

Oxygen (O) is in Period 2. Zinc (Zn) is in Period 4. Rubidium (Rb) is in Period 5. As the period number increases, the number of electron shells increases.

Step2: List the order

Since O has the fewest electron shells, followed by Zn, and Rb has the most electron shells, the order from least to greatest atomic radius is (O<Zn<Rb).

Answer:

4. (Na<K<Cs)
5. (P < Al<Mg)
6. (O<Zn<Rb)