Which of the following elements are fourth period semimetals? ...

[genevieve1028]

Which of the following elements are fourth period semimetals?
 
  A) Si and Ge
  B) Ge and As
  C) Sb and Te
  D) Po and At
  E) none of the above

Question 2

How many milliliters of 0.550 M hydriodic acid are needed to react with 15.00 mL of 0.217 M CsOH? HI(aq) + CsOH(aq)  CsI(aq) + H2O(l)
 
  A) 0.0263 mL
  B) 0.169 mL
  C) 5.92 mL
  D) 38.0 mL

Question 3

If we start with 1.000 g of cobalt-60, 0.400 g will remain after 7.00 yr. This means that the half-life of cobalt-60 is ________ yr.
 
  A) 12.1
  B) 17.5
  C) 2.80
  D) 5.30
  E) 7.65

[irishcancer18]

Answer to Question 1

B

Answer to Question 2

C

Answer to Question 3

D

[genevieve1028]

Wow, this really help

[cdmart10]

Excellent