Question

what can you learn about chlorine based on its position on the periodic table? (choose all that apply)

• chlorine is in group 17.
• chlorine has properties similar to f and br.
• chlorine is a halogen.
• chlorine is in the third period.

12 multiple answer 1 point
microwaves are less dangerous than x - rays because microwaves are
on - ionizing\, while x - rays are \ionizing\. what makes x - rays \ionizing\? (choose all that apply)

• like alpha particles, they are charged.
• they have enough energy to remove electrons.
• they dont really \ionize\ anything; they are just called \ionizing\ because they are dangerous.
• they are generated from ions.

13 multiple choice 1 point
bromine exists at two isotopes: bromine - 79 and bromine - 81. the atomic mass of bromine is 79.9 amu. what can you infer about the isotopic abundance of the two isotopes from this information?

• most naturally occurring bromine is the br - 79 isotope.
• isotopic abundance and atomic mass are unrelated.
• half of the naturally occurring bromine atoms are br - 79 and half are br - 81.
• most naturally occurring bromine is the br - 81 isotope.

Explanation:

Question 1 (Chlorine on Periodic Table)

• Group 17: Halogens are in group 17, so Cl being in group 17 is correct.
• Similar to F and Br: F, Cl, Br are halogens (group 17), so similar properties.
• Halogen: Cl is a halogen (group 17 elements are halogens).
• Third period: Cl is in period 3 (row 3) of the periodic table.

• X - rays ionize because they have enough energy to remove electrons (ionization is electron removal). Alpha particles are charged but X - rays are electromagnetic radiation (not particles), so first option wrong. They do ionize (remove electrons), so third option "They don't really..." wrong. X - rays aren't generated from ions, so last option wrong.

Atomic mass (79.9 amu) is a weighted average of isotopes' masses. 79.9 is closer to 79 than 81, so most naturally occurring Br is Br - 79. Isotopic abundance and atomic mass are related (atomic mass = sum(isotope mass × abundance)). Half of each would give atomic mass 80 ( (79 + 81)/2 = 80), not 79.9.

Answer:

A. Chlorine is in group 17.
B. Chlorine has properties similar to F and Br.
C. Chlorine is a halogen.
D. Chlorine is in the third period.

Question 12 (X - rays Ionizing)