Safety, Scientific Math, & Atomic Structure Review

The diagram above shows the approximate distance between the earth and the moon. How would this number be correctly expressed in scientific notation?

• 3.84 × 10⁴ km

• 3.84 × 10⁵ km

• 3.84 × 10⁶ km

• 0.384 × 10⁶ km

A scientist examines a sample of an unknown metal. She isolates several atoms which contain 29 protons and 35 neutrons. Which of the following isotopes has she isolated?

• Bromine-29

• Copper-64

• Chlorine-35

• Gadolinium-35

Which of the following is not an accurate conclusion that Thomson drew from his experiment?

• The beam was negatively charged since it was attracted to a positive charge.

• The beam was emitted from the nucleus of atoms because light was given off.

• The beam was made of particles because it was bent by a simple magnet.

• The beam was much smaller than hydrogen based on the mass to charge ratio.

An unknown element, Z, is examined and three isotopes are determined to be present.

⁸⁸Z = 2.24%, ⁹⁰Z = 78.32%, ⁹¹Z = 19.44%.

What is the atomic mass of the unknown element X according to this data set?

• 88.4 grams

• 90.1 grams

• 90.6 grams

• 89.2 grams

0.0500 m

How many significant figures are in the number shown above?

• 1 significant figures

• 4 significant figures

• 3 significant figures

• 5 significant figures

During a review lesson over volume, students were required to find the volume of different solid objects in a graduated cylinder using the displacement method. Below are four student calculations taken from this lab. Which student performed all calculations correctly and reported his or her answer to the correct number of significant figures?

• 13.6 mL - 9 mL = 4.6 mL

• 21 mL - 8.2 mL = 13 mL

• 30.0 mL - 20.0 mL = 10. mL

• 10.5 mL - 2 mL = 8 mL

Which of these conclusions can be drawn from Rutherford's experiment?

• The nucleus of an atom can be split.

• Each atom contains electrons.

• Each atom contains protons.

• Atoms are mostly empty space.

A scientist examines a sample of an unknown nonmetal. She isolates several atoms which contain 53 protons and 74 neutrons. Which of the following isotopes has she isolated?

• Iodine-127

• Tungsten-184

• Arsenic-74

• Chromium-53

C-12 and C-13 are naturally-occurring isotopes of the element carbon. C-12 occurs 98.89% of the time and C-13 occurs 1.108% of the time. What calculation should be used to determine the atomic mass of this element?

• (12 × 0.9889) − (13 × 0.01108)

• (12 × 0.9889) + (13 × 0.01108)

• (12 × 0.9889)

• (12 × 0.01108) + (13 × 0.9889) / 2

A nuclear scientist measures the distance between two carbon atoms that share a single sigma bond. It is determined that the distance between the carbon atoms is 1.54 x 10^-10 meters. Which of the numbers below also represents the distance between these carbon atoms?

• 0.000 000 000 154 m

• 0.000 000 001 54 m

• 0.000 000 000 015 4 m

• 15 400 000 000 m