Mass Number and Atomic Structure

The video tutorial explains the concept of mass number, which is the sum of protons and neutrons in an atom's nucleus. It introduces the atomic structure, highlighting the roles of protons, neutrons, and electrons. The mass number is represented by the symbol 'A' and is calculated using the formula A = Z + N, where Z is the atomic number (protons) and N is the number of neutrons. Examples are provided to illustrate mass number calculation. The video also explains how to find the mass number in the periodic table and discusses isotopes, which have the same number of protons but different numbers of neutrons, resulting in different mass numbers.

What is the mass number of an atom?

• The sum of protons and neutrons in the nucleus

• The number of neutrons in an atom

• The number of protons in an atom

• The number of electrons in an atom

Which symbol is used to represent the mass number?

• A

• Z

• M

• N

In an atom with 2 protons and 2 neutrons, what is the mass number?

• 6

• 4

• 2

• 8

What is the charge of a neutron?

• Variable

• Neutral

• Negative

• Positive

Which of the following is true about protons?

• They have a positive charge

• They have a variable charge

• They have no charge

• They have a negative charge

Where can you find the mass number of an element in the periodic table?

• Bottom left corner

• Top right corner

• Bottom center

• Top left corner

What is the mass number of an isotope of hydrogen with one neutron?

• 1

• 2

• 3

• 4

How does the mass number of isotopes differ?

• Different number of protons

• Different number of electrons

• Different number of neutrons

• Different atomic numbers

What is the atomic number of hydrogen?

• 3

• 4

• 1

• 2

What is the mass number of tritium?

• 4

• 1

• 2

• 3