Counting Protons, Neutrons, and Electrons in Atoms

This video tutorial by Mr. Millings covers the basics of counting subatomic particles, focusing on atomic numbers, average atomic mass, and mass numbers. It explains how atomic numbers represent the number of protons and electrons in an atom, and how the periodic table is organized by increasing atomic numbers. The video also delves into average atomic mass, which is calculated using the masses and relative abundances of isotopes. Additionally, it distinguishes between average atomic mass and mass number, the latter being the sum of protons and neutrons. The tutorial includes examples and practice problems to reinforce understanding.

What does the atomic number of an element represent?

• The number of neutrons in the nucleus

• The number of protons in the nucleus

• The number of electrons in the electron cloud

• The total mass of the atom

Which element has an atomic number of 19?

• Bromine

• Sodium

• Calcium

• Potassium

How is the average atomic mass of an element calculated?

• By adding the number of protons and neutrons

• By averaging the masses of all isotopes

• By counting the number of electrons

• By multiplying the masses of isotopes by their natural abundance and summing them

What is the average atomic mass of potassium if its isotopes have masses of 39, 40, and 41?

• 39.13

• 40.00

• 41.00

• 39.00

What is the mass number of an atom?

• The number of protons

• The average mass of isotopes

• The number of neutrons

• The sum of protons and neutrons

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

• Subtract the atomic number from the mass number

• Divide the mass number by the atomic number

• Multiply the atomic number by the mass number

• Add the atomic number to the mass number

What is the number of neutrons in carbon-14?

• 6

• 12

• 14

• 8

If an isotope of cobalt has a mass number of 59 and an atomic number of 27, how many neutrons does it have?

• 32

• 86

• 27

• 59

What is the mass number of an isotope of calcium with 20 protons and 21 neutrons?

• 42

• 21

• 20

• 41

How many neutrons are in an isotope of aluminum with a mass number of 28 and an atomic number of 13?

• 41

• 28

• 13

• 15