Question

practice:

1. identify the correct family.
2. explain the reasoning based on valence electrons and/or properties

element description|family?|why?
barium (ba)- a reactive metal used in medical imaging and fireworks
iodine (i)- a dark purple solid that has 7 valence electrons
radon (rn)- a radioactive gas that is chemically nonreactive
strontium (sr)- a reactive metal with 2 valence electrons
cesium (cs)- a metal that reacts with water

Explanation:

Step1: Analyze Barium

Barium has 2 valence electrons and is a reactive metal. Elements in Group 2 (alkaline - earth metals) have 2 valence electrons and are reactive metals. So, Barium is in the alkaline - earth metals family.

Step2: Analyze Iodine

Iodine has 7 valence electrons. Elements in Group 17 (halogens) have 7 valence electrons. So, Iodine is in the halogen family.

Step3: Analyze Radon

Radon is a radioactive gas and chemically non - reactive. Elements in Group 18 (noble gases) are chemically non - reactive gases. So, Radon is in the noble gases family.

Step4: Analyze Strontium

Strontium has 2 valence electrons and is a reactive metal. Elements in Group 2 (alkaline - earth metals) have 2 valence electrons and are reactive metals. So, Strontium is in the alkaline - earth metals family.

Step5: Analyze Cesium

Cesium is a metal that reacts with water. Elements in Group 1 (alkali metals) are highly reactive metals that react vigorously with water. So, Cesium is in the alkali metals family.

Answer:

Element Description	Family?	Why?
Iodine (I) - a dark purple solid that has 7 valence electrons	Halogens	Has 7 valence electrons
Radon (Rn) - a radioactive gas that is chemically nonreactive	Noble gases	Chemically non - reactive
Strontium (Sr) - a reactive metal with 2 valence electrons	Alkaline - earth metals	Has 2 valence electrons
Cesium (Cs) - a metal that reacts with water	Alkali metals	Reacts with water, typical of Group 1 metals