Understanding Atomic Numbers and Elements

The video tutorial explains how to identify elements based on their atomic number, which corresponds to the number of protons in an element. Using the periodic table, it demonstrates that sodium is the element with an atomic number of 11, meaning it has 11 protons. The tutorial emphasizes that each element has a unique atomic number, serving as a distinct identifier. For instance, if an element had 12 protons, it would be magnesium. This concept is crucial for understanding the organization of the periodic table and the identification of elements.

What is the first step in determining which element has 11 protons?

• Check the atomic mass on the periodic table.

• Find the atomic number on the periodic table.

• Look for the element symbol.

• Count the number of electrons.

What does the atomic number of an element represent?

• The number of electrons in the element.

• The atomic mass of the element.

• The number of neutrons in the element.

• The number of protons in the element.

Which element is identified by having an atomic number of 11?

• Potassium

• Aluminum

• Sodium

• Magnesium

Why is the atomic number considered a unique identifier for elements?

• It changes with the number of electrons.

• It is the same for all elements in a period.

• It uniquely determines the number of protons in an element.

• It varies with the atomic mass.

If an element has 12 protons, which element is it?

• Aluminum

• Magnesium

• Sodium

• Calcium

What would be the element if it had one more proton than sodium?

• Aluminum

• Magnesium

• Neon

• Chlorine