Mass Number Versus Atomic Mass in Atoms and Isotopes

The video tutorial explains the difference between mass number and atomic mass. Mass number is the sum of protons and neutrons in an atom's nucleus, while atomic mass is the weighted average of all isotopes of an element, considering their abundance. The tutorial uses boron as an example, showing how to calculate atomic mass by considering the different isotopes and their respective abundances. The video emphasizes the importance of understanding these concepts for interpreting the periodic table and determining the average atomic weight of elements.

What is another term often used for atomic mass?

• Proton mass

• Atomic number

• Average atomic mass

• Molecular weight

How is the mass number of an atom determined?

• By measuring the atomic radius

• By adding the number of protons and neutrons

• By counting the electrons

• By calculating the electron configuration

What does the mass number of an atom indicate?

• The number of electrons

• The type of chemical bonds it can form

• The element's position on the periodic table

• The total number of protons and neutrons

What defines isotopes of an element?

• Same number of electrons, different protons

• Same number of protons, different neutrons

• Different number of protons and electrons

• Same number of neutrons, different electrons

Which of the following is true about boron isotopes?

• Boron 10 and Boron 11 have different atomic numbers

• Boron 10 is more abundant than Boron 11

• Boron 11 has more neutrons than Boron 10

• Both isotopes have the same mass number

What percentage of boron atoms are Boron 11?

• 20%

• 50%

• 80%

• 100%

Why can't we simply average the mass numbers of isotopes to find atomic mass?

• Because isotopes have the same number of protons

• Because isotopes are not found in nature

• Because isotopes have different abundances

• Because isotopes have different chemical properties

How do you calculate the atomic mass of an element?

• By counting the total number of atoms

• By averaging the mass numbers of all isotopes

• By measuring the element's density

• By considering the abundance and mass of each isotope

What is the average atomic mass of boron as calculated in the video?

• 10.0 amu

• 11.0 amu

• 10.5 amu

• 10.8 amu

Where can you find the atomic mass of an element?

• In the nucleus

• In a chemical reaction

• On the periodic table

• In the electron cloud