Question

rank the following in order of increasing atomic radius

1. f
2. s
3. cl

question 4 (1 point)
rank the following in order of decreasing atomic radius

1. mg
2. be
3. na

question 5 (1 point)
what element is represented by 1s2 2s2 2p6 3s2 3p6 4s2?
a be
b sr
c ca
d mg

Explanation:

Step1: Recall atomic - radius trends

Atomic radius decreases across a period and increases down a group in the periodic table.

Step2: Analyze F, S, Cl

F is in period 2, S is in period 3 and Cl is in period 3. Among S and Cl, Cl is to the right of S in the same period. So, the order of increasing atomic radius is F < Cl < S.

Step3: Analyze Mg, Be, Na

Be is in period 2, Mg is in period 3 and Na is in period 3. Among Na and Mg, Na is to the left of Mg in the same period. So, the order of decreasing atomic radius is Na > Mg > Be.

Step4: Determine element from electron - configuration

The electron - configuration 1s²2s²2p⁶3s²3p⁶4s² has a total of 2 + 2+6 + 2+6 + 2=20 electrons. The element with 20 electrons is calcium (Ca).

Answer:

Question 3: 1. F, 3. Cl, 2. S
Question 4: 3. Na, 1. Mg, 2. Be
Question 5: c. Ca