المادة وتركيبها: العدد الكتلى والعدد الذرى

The video tutorial explains the concepts of mass and atomic numbers in chemistry, using the sodium atom as an example. It describes how the mass number is the sum of protons and neutrons, while the atomic number represents the number of protons. The tutorial also demonstrates how to calculate the number of neutrons by subtracting the atomic number from the mass number. This understanding is crucial for identifying and describing elements.

What do the numbers around chemical symbols represent?

• Atomic mass and atomic number

• Atomic weight and electron count

• Proton count and electron count

• Neutron count and atomic weight

How is the atomic mass of an element determined?

• By summing the number of protons and neutrons

• By counting the total number of electrons

• By subtracting the atomic number from the mass number

• By adding the number of protons and electrons

In the example of sodium, what is the atomic mass?

• 11

• 34

• 23

• 12

What does the atomic number of an element indicate?

• The number of protons in the nucleus

• The total number of neutrons

• The number of electrons in the outer shell

• The sum of protons and neutrons

How can you calculate the number of neutrons in an atom?

• By adding the atomic number and atomic mass

• By subtracting the atomic number from the atomic mass

• By dividing the atomic mass by the atomic number

• By multiplying the atomic number by the atomic mass