4.1.2 Atomic Number and Mass Number

• The atomic number of an element is the number of protons found in the nucleus of an atom.
• Match each element with its atomic number:

  Hydrogen ↔️ 1

  Carbon ↔️ 6

  Oxygen ↔️ 8
• The mass number of an element is unique to that element.

  False
• Arrange the following properties based on their location on the Periodic Table:

  1️⃣ Atomic Number (above element symbol)

  2️⃣ Mass Number (below element symbol)
• Match each element with its relationship between atomic number and number of protons:

  Hydrogen ↔️ Atomic Number = 1, Protons = 1

  Carbon ↔️ Atomic Number = 6, Protons = 6

  Oxygen ↔️ Atomic Number = 8, Protons = 8
• Each element has a unique atomic number.


  True
• Unlike the atomic number, the mass number can vary among isotopes
• What does the atomic number of an element identify?

  Number of protons
• The mass number of an element is the total number of protons and neutrons
• The atomic number is the number of protons in an atom.


  True
• The mass number is the total number of protons and neutrons
• The mass number of an element is the total number of protons and neutrons
• The atomic number is typically located above the element symbol on the Periodic Table.
• Match the property with its location on the Periodic Table:

  Atomic Number ↔️ Above element symbol

  Mass Number ↔️ Derived from protons and neutrons
• The mass number can vary among isotopes of the same element
• The mass number is the sum of protons and neutrons in the nucleus.

  True
• Arrange the following steps to calculate the number of neutrons:

  1️⃣ Identify the mass number

  2️⃣ Identify the atomic number

  3️⃣ Subtract the atomic number from the mass number
• Isotopes have the same number of protons but different numbers of neutrons
• The atomic number of an element is unique to that element.

  True
• The mass number of an element is the total number of protons and neutrons in the nucleus.
• Match each element with its mass number:

  Hydrogen ↔️ 1

  Carbon ↔️ 12

  Oxygen ↔️ 16
• The atomic number on the Periodic Table represents the number of protons in the nucleus of an atom.
• The mass number is explicitly shown on the Periodic Table.

  False
• What does the atomic number of an element represent?

  Number of protons
• In each case, the Atomic Number equals the number of protons
• What is the mass number of an element?

  Protons + neutrons
• The atomic number is located above the element symbol on the Periodic Table.


  True
• How do you calculate the number of neutrons in an atom?

  Mass number - atomic number
• What can vary among isotopes of the same element?

  Mass number
• Steps to find atomic number and mass number on the Periodic Table

  1️⃣ Locate the element symbol

  2️⃣ Find the atomic number above the symbol

  3️⃣ Calculate the mass number using protons and neutrons
• The atomic number is unique to each element and defines it.


  True
• The atomic number represents the number of protons in the nucleus of an atom.


  True
• The atomic number is unique to each element
• To calculate the number of neutrons, you subtract the atomic number from the mass number
• The formula to calculate the number of neutrons is: Mass number - Atomic number = Number of neutrons
• Isotopes of an element have the same atomic number but different mass numbers.

  True