Use the periodic to fill in the numbers in the electron configurations shown below. B: 1s2 2sA2pB

A =

B =

Which statement justifies that hydrogen peroxide (H2O2) is a polar molecule? The O - H bond is nonpolar and the molecule is asymmetric. The O - H bond is nonpolar and the molecule is symmetric. The O - H bond is polar and the molecule is asymmetric.

What is the particle's position at t = 3.0s? express your answer to three significant figures and include the appropriate units?

What element is used as a shield to protect people from radioactive substances?

A gaseous substance turns into a solid. Which best describes this change?

Calculate the ph of a solution formed by mixing 250.0 ml of 0.15 m nh4cl with 100.0 ml of 0.20 m nh3. the kb for nh3 is 1.8 x 10-5.

Which of the following likely formed Mars' moons?

Which process involves mass movement within a substance? a. conduction b. convection c. radiation d. reflection

A scientist observes that the electrical resistance of a superconducting material drops to zero when the material is cooled to very low temperatures. Which of the following statements best describes what the scientist is observing?

Which describes an object's speed in free fall? a. The object accelerates until it reaches its terminal velocity. b. The object falls at a constant speed because only one force acts on it. c.

Which metal can be cutted easiy?