Counting Protons, Neutrons, and Electrons in Atoms

The video tutorial covers the basics of atomic structure, focusing on counting protons, neutrons, and electrons. It introduces three key rules: the atomic number equals the number of protons, the number of protons equals the number of electrons in a neutral atom, and the mass number is the sum of protons and neutrons. The tutorial uses xenon as an example to demonstrate these concepts, explaining how to calculate the number of neutrons using the mass number and protons. It also discusses the difference between mass number and average atomic mass, emphasizing the importance of rounding. The session concludes with an assignment to fill out a chart based on the discussed concepts.

What materials are needed for the lesson on atomic structure?

• A computer and a lab coat

• A calculator and a notebook

• A periodic table and a packet

• A textbook and a ruler

Tags

NGSS.MS-PS1-1

What does the atomic number of an element represent?

• The atomic mass

• The number of protons

• The number of electrons

• The number of neutrons

If an element has an atomic number of 54, how many protons does it have?

• 54

• 108

• 131

• 27

In a neutral atom, the number of protons is equal to the number of what?

• Neutrons

• Electrons

• Atoms

• Molecules

What is the symbol for an electron?

• n neutral

• p positive

• e positive

• e negative

What two particles are added together to find the mass number of an atom?

• Protons and electrons

• Neutrons and electrons

• Neutrons and atoms

• Protons and neutrons

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

• Multiply the atomic number by the mass number

• Add the atomic number to the mass number

• Divide the atomic number by the mass number

• Subtract the atomic number from the mass number

What is the mass number of xenon if its atomic mass is 131.30?

• 132

• 131

• 133

• 130

If xenon has 54 protons and a mass number of 131, how many neutrons does it have?

• 77

• 185

• 131

• 54

What is the average atomic mass of xenon?

• 131.30

• 131

• 77

• 54