Atomic Structure and Isotopes Worksheet

Which two particles each have a mass approximately equal to one atomic mass unit?

• positron and electron

• positron and neutron

• proton and electron

• proton and neutron

Which description of the atom is based on the results of the gold foil experiment in the early 1900s?

• Atoms are small, dense, indivisible spheres

• Atoms are composed of protons, electrons, and neutrons

• Atoms have small, dense, positively charged nuclei.

• Atoms have electrons with wavelike properties.

On the Periodic Table, the number of protons in an atom of an element is indicated by its

• atomic mass

• atomic number

• selected oxidation states

• number of valence electrons

Every chlorine atom has

• 7 electrons

• 17 neutrons

• a mass number of 35

• an atomic number of 17

The table below gives the atomic mass and the abundance of the two naturally occurring isotopes of copper. Which numerical setup can be used to calculate the atomic mass of the element copper?

• (62.93 u)(30.85) + (64.93 u)(69.15)

• (62.93 u)(69.15) + (64.93 u)(30.85)

• (62.93 u)(0.3085) + (64.93 u)(0.6915)

• (62.93 u)(0.6915) + (64.93 u)(0.3085)

A potassium atom has a mass number of 37. What is the number of neutrons in this atom?

• 15

• 18

• 22

• 37

Which phrase describes the different isotopes of an element?

• same number of electrons and a different number of protons

• same number of protons and a different number of electrons

• same number of protons and a different number of neutrons

• same number of neutrons and a different number of protons

Which two notations represent isotopes of the same element?

• ¹⁴₇ N and ¹⁸₇ N

• ²⁰₇ N and ²⁰₁₀ Ne

• ¹⁴₇ N and ¹⁷₁₀ Ne

• ¹⁹₇ N and ¹⁶₁₀ Ne

Which numerical setup can be used to calculate the atomic mass of the element bromine?

• (78.92 u)(50.69) + (80.92 u)(49.31)

• (78.92 u)(49.31) + (80.92 u)(50.69)

• (78.92 u)(0.5069) + (80.92 u)(0.4931)

• (78.92 u)(0.4931) + (80.92 u)(0.5069)

An orbital is defined as a region of the most probable location of

• an electron

• a neutron

• a nucleus

• a proton