Decoding Atomic Number and Mass

The video tutorial explains how to use the periodic table to understand the physical properties of elements, using carbon as an example. It covers the concepts of atomic number, which indicates the number of protons in an atom, and atomic mass, which is the sum of protons and neutrons. The tutorial also discusses the balance of protons and electrons in neutral atoms and how to calculate the number of neutrons by subtracting the atomic number from the atomic mass. The concept of isotopes and their impact on atomic mass is also explained.

What does the atomic number of an element represent?

• Total mass of the atom

• Number of protons

• Number of electrons

• Number of neutrons

What is the atomic number of carbon?

• 6

• 12

• 8

• 14

Why does a neutral atom of carbon have 6 electrons?

• Because it has 6 neutrons

• To balance the protons

• Because it is a stable configuration

• To balance the neutrons

Tags

NGSS.MS-PS1-1

What must be true for an atom to be neutral?

• Equal number of protons and neutrons

• Equal number of electrons and neutrons

• Equal number of protons and electrons

• More protons than electrons

What is generally excluded from calculations of atomic mass?

• Isotopes

• Electrons

• Neutrons

• Protons

Why are electrons usually ignored in mass calculations?

• They are outside the nucleus

• They have no charge

• They have negligible mass

• They do not affect chemical properties

Tags

NGSS.MS-PS1-5

What causes the atomic mass of carbon to be 12.01?

• It has 12 protons

• It has 12 neutrons

• Average of all isotopes

• Presence of heavy isotopes

What is the significance of the atomic mass 12.01 for carbon?

• It is a theoretical value

• It is the sum of protons and neutrons

• It is the sum of protons and electrons

• It represents the average mass of all isotopes

How do you calculate the number of neutrons in carbon?

• Add atomic number and atomic mass

• Subtract atomic number from atomic mass

• Add protons and electrons

• Subtract the number of electrons from atomic mass