Unit 1 Review

Which isotope has a larger percent abundance, Cl-35 or Cl-37, given that the average atomic mass of Chlorine is 35.45 amu?

• Cl-35

• Cl-37

• both have the same percentage

• cannot be determined from this data

An element has two isotopes. One isotope has a relative abundance of 75.0% and mass 25.0 amu. The second isotope has a relative abundance of 25.0% and 28.0 amu. What is the average atomic mass of the element?

• 26.5 amu

• 25.8 amu

• 27.3 amu

• 258 amu

Element C has both a different mass number and identity than elements A and B

• TRUE

• FALSE

Which two atoms are isotopes of one another?

• Atoms 1 & 2

• Atoms 2 & 3

• Atoms 1 & 3

• Atoms 1 & 4

What did Rutherford discover about atoms?

• An atom is always negatively charged.

• An atom is mostly empty space, but has a dense positively charged center(nucleus).

• An atom is always positively charged.

• All particles will pass straight through gold foil with no change in path.

Why is Model B incorrect and Model A correct?

• Because electrons are suppose to absorb energy, release a photon of light, and jump to a higher energy level before falling back down.

• Because electrons are suppose to absorb energy and jump to a higher energy level. As they fall back down that energy is released as a photon of light.

Which element has the following electron configuration?

• Selenium (Se)

• Arsenic (As)

• Vanadium (V)

• Phosphorus (P)

What electron configuration matches the ion: Al ⁺³

• 1s²2s²2p⁶3s²3p⁴

• 1s²2s²2p⁶

• 1s²2s²2p⁶3s²3p¹

• 1s²2s²2p⁶3s²