Atomic Structure Review

Which part of the atom contains most of the mass?

• Electrons

• Nucleus

• Protons

• Neutrons

Tags

NGSS.HS-PS1-8

Determine the atomic number, mass number, number of protons, neutrons, and electrons for a neutral atom of potassium-39.

• Atomic # 19

  Mass # 39

  Protons 19

  Neutrons 20

  Electrons 19

• Atomic # 19

  Mass # 39.098

  Protons 19

  Neutrons 19

  Electrons 19

• Atomic # 39

  Mass # 19

  Protons 39

  Neutrons 19

  Electrons 39

• Atomic # 19

  Mass # 39.098

  Protons 19

  Neutrons 20

  Electrons 19

Isotopes have the same number of ____, but different number of ____.

• neutrons; protons

• protons; electrons

• protons + electrons; neutrons

• electrons; protons

Tags

NGSS.HS-PS1-8

Naturally occurring chlorine that is put in pools has an average atomic mass of 35.46 amu. The two isotopes that exist are chlorine-35 and chlorine-37. Which isotope is more abundant?

• Chlorine-35

• Chlorine-37

In a neutral atom what two subatomic particles are equal?

• Neutrons + Protons

• Electrons + Neutrons

• Protons + Electrons

How many neutrons are in carbon-14?

• 6

• 8

• 7

• 14

Tags

NGSS.HS-PS1-8

What steps do you take when calculating the average atomic mass of an element?

• 1. Add up the atomic masses of each isotope
  2. Divide by the number of isotopes there are
• 1. Multiply the atomic mass of each isotope by its percent abundance divided by 100
  2. Sum the products
• 1. Multiply the atomic mass of each isotope by its percent abundance divided by 100
  2. Sum the products
  3. Divide by the number of isotopes there are
• 1. Multiply the atomic mass of each isotope by the percent abundance
  2. Sum the products

There are two naturally occuring isotopes of lithium, lithium-7 and lithium-6. If the average atomic mass is 6.941 which isotope is more abundant?

• Neither, same abundance

• Lithium-6

• Lithium-7

The table below gives the atomic mass and the abundance of the two naturally occurring isotopes of bromine.

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)

The average isotopic mass of chlorine is 35.5. Which mixture of isotopes (shown as percents) produces this average mass?

• 50% ¹²C and 50% ¹³C

• 50% ³⁵Cl and 50% ³⁷Cl

• 75% ¹²C and 25% ¹³C

• 75% ³⁵Cl and 25% ³⁷Cl