Unit 1-1 Study Guide

Which isotope has the greatest number of protons?

• Pa-238

• U-240

• Np-238

• Pu-239

A neutral atom has a ground state electron configuration of 1s²2s²2p⁶3s². The neutral atom becomes an ion during a chemical reaction. Which is the most likely charge of the ion?

• +2

• +1

• -2

• -6

Which of the following distinguishes the isotope uranium-238 from the isotope uranium-235?

• Number of Neutrons in the Nucleus

• Location on the Periodic Table

• Amount of Negative Charge

• Ability to Form Ions

This table shows the naturally occurring isotopes of the element sulfur.

What is the average atomic mass of sulfur?

• 32.06 amu

• 32.39 amu

• 33.75 amu

• 34.12 amu

The element lanthanum has an isotope with an atomic mass of 138.9 amu and an abundance of 99.91%. A second isotope has an atomic mass of 137.9 amu and an abundance of 0.09%. What is the average atomic mass of lanthanum?

• 138.4 amu

• 138.8 amu

• 138.9 amu

• 139.0 amu

Which part of an atom has the least mass?

• electron

• nucleus

• neutron

• proton

The Periodic Table entry for Beryllium is shown above.

Beryllium has a single naturally occurring isotope. Which Isotopic Notation correctly represents Beryllium?

• ⁴₅Be

• ⁴₉Be

• ⁵₄Be

• ⁹₄Be

Which statement explains why MOST of the mass of an atom is contained in the relatively small nucleus?

• Atoms are composed of less dense subunits than the nucleus.

• Protons and neutrons have more mass than electrons.

• The nucleus is located at the center of an atom.

• Atoms are composed of mostly empty space.

Which statement describes the relationship between the nucleus of an atom and the atom itself?

• The Nucleus determines the Size of the Atom.

• The Nucleus determines the Shape of the Atom.

• The Nucleus contains most of the mass of the Atom.

• The Nucleus contains the protons and electrons of the Atom.

Matter can be organized into the levels shown above.

What is the correct order from SMALLEST to LARGEST

• 2-4-3-1

• 3-4-1-2

• 4-2-1-3

• 2-3-4-1