21. draw the electron dot structure for each element.\na. sr\nb. sn\nc. te\ninvestigation 2

Explanation:

Step1: Determine valence electrons for Sr

Strontium (Sr) is in group 2, has 2 valence electrons. Electron - dot structure has 2 dots around Sr symbol.

Step2: Determine valence electrons for Sn

Tin (Sn) is in group 14, has 4 valence electrons. Electron - dot structure has 4 dots around Sn symbol.

Step3: Determine valence electrons for Te

Tellurium (Te) is in group 16, has 6 valence electrons. Electron - dot structure has 6 dots around Te symbol.

Answer:

a. Sr with 2 dots around it. b. Sn with 4 dots around it. c. Te with 6 dots around it.