What Is An Atom - Part 2 - Isotopes

This video tutorial covers the basics of atomic structure, focusing on atoms, isotopes, and how to determine mass numbers from the periodic table. It explains the significance of atomic and mass numbers, using sodium and chlorine as examples. The video also discusses electron configuration, detailing how electrons occupy energy levels or shells. By the end, viewers should understand the composition of atoms, the concept of isotopes, and how to calculate the number of fundamental particles in an element.

What does the atomic number of an element indicate?

• The total number of electrons and neutrons

• The number of neutrons in the nucleus

• The number of protons in the nucleus

• The average mass of the element

How many neutrons are present in a sodium atom with a mass number of 23?

• 23

• 12

• 11

• 34

Why is the atomic mass of chlorine not a whole number?

• It varies with temperature

• It is rounded to the nearest whole number

• It includes the mass of electrons

• It is an average of different isotopes

What determines the number of electrons each shell can hold?

• The atomic number of the element

• The row of the periodic table

• The mass number of the element

• The number of protons in the nucleus

Which of the following statements about electron shells is true?

• Electrons can move freely between shells

• Each shell can hold an unlimited number of electrons

• Electrons fill the innermost shells first

• The first shell can hold up to four electrons